Abstract. Kristina IG, Irawati W, Dikson, Pinontoan R. 2026. Genomic characterization of Escherichia coli Cn5 and IrN exhibiting copper resistance and malachite green decolorization. Biodiversitas 27 (6): d270623. https://doi.org/10.13057/biodiv/d270623. Copper and textile dye pollution pose significant environmental threats because of their adverse effects on aquatic ecosystems and human health. Bioremediation using indigenous bacteria has emerged as an effective, eco-friendly, and cost-efficient alternative to conventional treatments. However, genomic studies on bacteria exhibiting both heavy-metal resistance and dye decolorization remain limited. This study served as a preliminary evaluation of indigenous bacterial isolates from Indonesia for their copper (Cu) resistance and Malachite Green (MG) decolorization phenotypes and genotypes. Phenotype assessment involved their growth and activity on liquid and solid Luria-Bertani media supplemented with increasing concentrations of CuSO4 or MG. Genotype assessment involved Nanopore whole-genome sequencing and annotation to determine taxonomic identity and putative functional genes. Two isolates, Cn5 and IrN, tolerated up to 12 mM CuSO₄ and 20 ppm MG dye. The MG decolorization assays revealed efficiencies of 90.8% for isolate Cn5 and 93.4% for isolate IrN after 4 days of incubation, indicating bioremediation potential. Whole-genome comparison, multilocus sequence typing, and phylogenetic analysis confirmed that both isolates belong to Escherichia coli. Comparative genomics identified gene clusters putatively associated with Cu resistance, including cop, cue, and cus genes. Functional annotation revealed four reductase genes, one peroxidase gene, and one laccase-encoding gene potentially involved in MG dye decolorization. This study provides a preliminary genomic characterization of E. coli strains combining Cu resistance and MG decolorization as a baseline for further investigation of their bioremediation-related potential.
Abstract. Kalam ZB, Arselan A, Khaerudi D, Arafat D, Zamani NP, Natih NMN, Haryanto RRR, Puspa I, Agus SB, Subhan B. 2026. Contrasting bleaching severity between marine protected and coral restoration areas on Pramuka Island, Indonesia. Biodiversitas 27 (5): d270531. https://doi.org/10.13057/biodiv/d270531. The 2023-2024 global coral bleaching event provided an urgent context for assessing reef responses under contrasting management regimes. This study compared bleaching prevalence, hard coral cover, genus composition, and life-history strategy distributions between a Marine Protected Area (MPA) and an active coral restoration site (RPTRA Smiling Coral) on Pramuka Island, Thousand Islands, Indonesia. Surveys were conducted in January 2024 using a rapid photo-quadrat method across three depth strata (5, 10, and 15 m) at both sites. The MPA exhibited severely degraded coral cover (below 25% at all depths) and extremely high bleaching prevalence (83.75-91.81%), with near-total bleaching in dominant genera including Pachyseris spp. and Pleuractis spp. In contrast, the RPTRA restoration site showed bleaching rates below 33% across all depths, with Porites spp. displaying more stable responses. Despite uniform water temperatures of 30°C across all depths, bleaching was most severe at 5 m, suggesting that light intensity amplifies thermal stress in shallow habitats. Critically, all four life-history strategies were represented among bleached genera, indicating that even stress-tolerant corals are approaching their thermal tolerance limits. These findings indicate that sites under active restoration were associated with substantially lower bleaching prevalence and better ecological condition than the passively protected MPA, consistent with the hypothesis that active restoration enhances post-bleaching recovery capacity. This association has implications for the long-term biodiversity resilience of coral communities under escalating climate stress, though the observational design precludes direct causal attribution.
Abstract. Hien PTT, Thoa TTK, Tam HM. 2026. DNA barcoding-based identification of Praxelis clematidea collected from Phu Tho Province, Vietnam. Biodiversitas 27 (6): d270616. https://doi.org/10.13057/biodiv/d270616. Praxelis clematidea, commonly known as praxelis, is a member of the family Asteraceae and is widely distributed in Vietnam. Morphological similarities with related taxa in Asteraceae often complicate accurate species identification. In this study, specimens of P. clematidea collected from Tu Vu Commune, Phu Tho Province, Vietnam (designated as P. clematidea TV) were identified using molecular markers. Four DNA barcode regions, including the nuclear ITS (Internal Transcribed Spacer) and three chloroplast markers (matK, rpoC1, and trnL), were amplified, sequenced, and analyzed phylogenetically. The resulting sequences were deposited in GenBank under accession numbers PX622467.1 (ITS), PX614615.1 (matK), PX614617.1 (rpoC1), and PX614618.1 (trnL). Phylogenetic analyses were performed using the Maximum Likelihood method implemented in Molecular Evolutionary Genetics Analysis version 12 (MEGA12). The ITS analysis placed P. clematidea TV together with P. clematidea (MN889429.1) with a bootstrap value of 96%. Similarly, matK grouped the sample with P. clematidea (accession numbers KX526581.1) with 96% bootstrap support, whereas trnL clustered it with P. clematidea (accession numbers KT002019.1 and KT002021.1) with a bootstrap value of 76%. The rpoC1 marker showed lower phylogenetic resolution, with the clade containing P. clematidea and Ageratum conyzoides (accession numbers MK905238.1) receiving a bootstrap value of 42%. These results demonstrate that the combined use of nuclear and chloroplast DNA barcodes provides reliable evidence for the identification and taxonomic placement of P. clematidea collected from Phu Tho Province, Vietnam.
Abstract. Scrivanti LR, Fuentes E, Robbiati FO, Nores MJ. 2026. Environmental gradients across the geographic range of Puya spathacea (Bromeliaceae). Biodiversitas 27 (6): d270611. https://doi.org/10.13057/biodiv/d270611. Puya spathacea is a terrestrial bromeliad native to northwestern Argentina and southern Bolivia, distributed across montane environments. This study evaluated spatial segregation and environmental variation of occurrence records, classified into central, intermediate, and peripheral zones based on their distance from the centroid of the species' range. We assessed spatial structure, analyzed altitudinal and climatic variation, and evaluated the relationship between occurrences and river networks, while also estimating potential distribution and characterizing environmental space. Ecological niche models showed high internal consistency (AUC = 0.952±0.019; TSS = 0.845±0.047), identifying elevation (38%) and precipitation of the wettest month (13.8%) as the most influential predictors of habitat suitability. PCA-env analyses explained 83.4% of environmental variation across the first two axes, while niche overlap among zones was low (Schoener’s D = 0.02-0.20), indicating differentiated environmental space. Spatial autocorrelation was stronger at the margins, and occurrences were significantly closer to rivers than expected by chance, indicating a non-random spatial association with the hydrological network rather than direct evidence of habitat dependence. Overall, peripheral occurrences occupied environmentally distinct conditions characterized by greater climatic restriction and spatial structuring than central occurrences. These findings indicate that geographically structured occurrences contribute to within-range environmental differentiation and highlight the importance of considering environmental variation across species distributions when evaluating montane biodiversity. From a conservation perspective, preserving both central and peripheral occurrences may be relevant for maintaining the ecological breadth of the species
Abstract. Sahid ZD, Qadir A, Syukur M, Ariyanto KF, Wijaya AK, Suwarno PM, Rusmiyati H, Hatta ANNL. 2026. Quantitative and qualitative morphological diversity among nine cherry tomato (Solanum lycopersicum) genotypes grown under lowland conditions. Biodiversitas 27 (6): d270622. https://doi.org/10.13057/biodiv/d270622. Cherry tomatoes are a type of tomato that has seen increasing market demand post-global pandemic as a healthy fruit. Cherry tomato cultivation is generally carried out in highlands and faces competition from other vegetable cultivation. Therefore, developing cherry tomato varieties adapted to lowland conditions is necessary. Developing new superior varieties requires basic information for selecting the diversity of the parents used. Therefore, this study aims to evaluate the morphological diversity of Institut Pertanian Bogor (IPB) cherry tomato lines as cross-breeding parents in further studies. The study was conducted at the lowland greenhouse teaching factory of the vocational school, Institut Pertanian Bogor, Bogor, using automated irrigation and fertigation systems and a single-factor randomized complete block design. The results of this study indicate that there is diversity among nine Institut Pertanian Bogor cherry tomato lines (hybrid and non-hybrid lines) that have the potential to be used as parents in the development of new superior varieties. The seed germination percentage measured in this study varied (80-95%), with early flowering and harvest times (26 and 62 days after transplanting). The average fruit length, diameter, and weight (3.28 cm, 19.24 mm, and 7.23 g) measured in this study showed a vast morphological divergence, making them potential parent lines in cherry tomato breeding. Cluster analysis of nine genotypes based on their morphological characteristics resulted in three main groups, from which parents for breeding were selected. IPBTC 147 forms a distinct group due to its unique morphological characteristics, both quantitative and qualitative, which significantly differ from other genotypes, particularly in its fruit shape and color. This genotype has an average fruit weight of 5 g with the longest fruit stalk length (2.27 cm). The yellow color of this fruit has the potential to produce high diversity in the F2 when crossed with red fruit color. The morphological performance information of this research is expected to serve as a consideration for selecting parents for the development of cherry tomatoes adapted to lowlands.
Abstract. Tirta N, Harnelly E, Fachri RF, Siregar PKA, Razi NM, Khaira NU, Ramadhaniaty M, Rahayu SR, Anggraini NP, Siregar RA, Damora A, Fadli N. 2026. New COI records of Myripristis kuntee (Pisces: Holocentridae) from Indonesia and preliminary genetic comparison with Asian public sequences. Biodiversitas 27 (5): d270530. https://doi.org/10.13057/biodiv/d270530. Shoulderbar soldierfish (Myripristis kuntee) is a reef-associated fish of ecological and economic importance widely distributed across the Indo-Pacific. However, molecular data for this species in Indonesian waters remain limited. This study provides the first cytochrome c oxidase subunit I (COI) based genetic record of M. kuntee from Indonesia and provides a preliminary genetic comparison with publicly available Asian sequences. Five specimens were collected in July 2024 from fishermen at a fish landing site in Ujung Pancu, Aceh Besar, Indonesia. A total of 27 mitochondrial COI sequences were analyzed, including five newly generated samples and 22 sequences retrieved from GenBank (Philippines, China, Taiwan, Bangladesh, and India). Sequence alignment and phylogenetic analyses were performed using MEGA, haplotype analyses were conducted in DnaSP, and genetic diversity indices were calculated using ARLEQUIN. Fifteen haplotypes were identified across six populations. The Philippines exhibited high haplotype diversity (Hd = 0.924; π = 0.025), while Indonesia showed moderate haplotype diversity (Hd = 0.700; π = 0.002), and Bangladesh exhibited no detectable variation. Genetic distances ranged from 0.002 between Indonesia and China to 0.219 between the Philippines and Bangladesh, suggesting close affinity between Indonesian and Chinese sequences but substantial mitochondrial divergence among some regional samples. Phylogenetic analysis revealed two clusters: China, the Philippines, Indonesia, and Taiwan grouped together, suggesting a close mitochondrial relationship, whereas Bangladesh clustered with one Indian sequence. These findings establish baseline COI barcode data for M. kuntee from Indonesia and provide preliminary insights into regional mitochondrial variation, although broader and more balanced sampling is required to confirm these patterns.
Abstract. Moulana R, Ismail YS, Yunita D, Izla D, Yulvizar C. 2026. Antimicrobial activity and metabolite profiling of lactic acid bacteria isolated from solid and liquid tofu waste. Biodiversitas 27 (6): d270621. https://doi.org/10.13057/biodiv/d270621. The production of tofu generates two types of waste by-products: solid (tofu pulp) and liquid (tofu whey). These by-products are rich in carbohydrates and proteins, which can support the growth of lactic acid bacteria (LAB). The objective of this study was to isolate and phenotypically characterize presumptive LAB isolates from tofu waste and to evaluate their antimicrobial activity against Escherichia coli, Staphylococcus aureus, and Candida albicans. Presumptive LAB were isolated using De Man, Rogosa, and Sharpe (MRS) agar supplemented with 1% CaCO₃ and phenotypically characterized based on Gram-positive reaction, catalase-negative activity, and cocci or rod-shaped cell morphology. Antimicrobial activity was evaluated using the disc diffusion method with cell-free supernatants (CFS) as a preliminary antimicrobial screening approach. The results showed that eight presumptive LAB isolates were obtained, consisting of three isolates from solid tofu waste (LPT1-LPT3) and five from liquid tofu waste (LCT1-LCT5). LPT1 demonstrated the largest inhibition zone against S. aureus (12.77 mm; strong category), while LCT1 exhibited the largest inhibition against E. coli (7.26 mm; moderate category). However, no antifungal activity was detected against C. albicans. GC-MS metabolite profiling of isolates LPT1 and LCT1 identified 18 chemical compounds, with acetic acid detected as the dominant metabolite in both isolates. These findings indicate that LAB isolated from tofu waste may represent a potential source of antimicrobial metabolites. However, further quantitative and molecular analyses are required to clarify the contribution of specific metabolites to the observed antibacterial activity.
Abstract. Truc NT, Dang KD, Thi QVC, Nhi NLY, Trong NM, Ut LV. 2026. Isolation and in vitro antagonistic activity of indigenous rhizosphere Trichoderma against Colletotrichum cf. musae causing banana anthracnose. Biodiversitas 27 (5): d270534. https://doi.org/10.13057/biodiv/d270534. Banana is a high-yielding and economically important export crop. However, anthracnose caused by Colletotrichum spp. is a causative agent that reduces fruit quality and shelf life. Trichoderma is known for its antagonistic activity against a wide range of plant pathogens, including Colletotrichum species. The aim of the present study was to isolate Trichoderma isolates from rhizosphere soil samples and to evaluate their antagonistic activity against Colletotrichum sp. In the present study, ten Colletotrichum isolates were obtained and identified from banana fruits showing anthracnose symptoms. Among them, isolate C12.1 was the most frequently isolated and identified as Colletotrichum cf. musae. Trichoderma species were isolated from 15 rhizosphere soil samples of banana plants. The results showed that a total of 16 Trichoderma isolates were isolated from 15 soil samples from banana plants collected from different areas in Vinh Long Province. All Trichoderma isolates exhibited strong antagonistic activity against Colletotrichum sp. Notably, isolates TC1, TC2, TC5, TC9, TC10, and TC11 demonstrated the highest in vitro inhibition of mycelial growth, ranging from 80.61% to 87.88%. Among these, isolate TC5, which exhibited both strong inhibitory activity (87.88%) and significant extracellular enzyme production, was selected for PCR amplification and sequencing of the internal transcribed spacer (ITS) region. Isolate TC5 was likely the closest relative to Trichoderma hamatum and was identified as T. hamatum. In addition, six selected Trichoderma isolates were qualitatively assessed for extracellular enzyme production. All tested isolates were positive for cellulase, amylase, β-1,3-glucanase, and chitinase. The production of these enzymes highlights their role in mycoparasitism and supports the potential of Trichoderma isolates as effective biocontrol agents. Although the findings demonstrate promising antagonistic potential, the results are currently limited to in vitro assays and qualitative enzyme detection. Therefore, further studies under in vivo conditions are required to validate their efficacy before practical field application.
Abstract. Sharip A, Abiyev S, Sitpayeva G, Kulymbet K, Osmonali B. 2026. Mericarpmorphometry and morphology of five Ferula species from the Ulytau region, Central Kazakhstan. Biodiversitas 27 (6): d270610. https://doi.org/10.13057/biodiv/d270610. This study presents a comparative morphological and morphometric analysis of mericarps from five Ferula species (Apiaceae) associated with the Ulytau region of Central Kazakhstan: Ferula karelinii, Ferula teterrima, Ferula varia, Ferula songarica, and Ferula ferulaeoides. A total of 150 mericarps (30 per species) were analyzed. Qualitative characters included mericarp size, color, shape, groove pattern, surface texture, and chalazal-end morphology, while quantitative parameters comprised mericarp mass and linear dimensions (length, width, diagonal length, apical width, and basal width). The results revealed clear interspecific differences in both qualitative and quantitative traits. The largest mericarps were recorded in F. karelinii, whereas the smallest were observed in F. ferulaeoides. Correlation analysis demonstrated strong positive relationships among linear mericarp parameters (r = 0.82–0.97), indicating a high degree of morphological integration. Regression analysis based on pooled data showed significant positive relationships between mericarp mass and dimensional traits (R² = 0.47-0.63; p<0.001). However, these relationships mainly reflected differences among species rather than consistent within-species allometric patterns. Species-specific analyses revealed considerable variation in mass–size relationships, including weak or negative correlations in some taxa. Although the relatively limited sample size and restricted geographic coverage require cautious interpretation, the results indicate that mericarp morphology and morphometry provide useful characters for comparative carpological studies of Ferula. Further research incorporating broader sampling, population-level analyses, and integrative taxonomic approaches is needed to evaluate the wider systematic significance of these traits.
Abstract. Irawan A, Hidayat T, Nilawati TS, Bangiel AFN, Iqbal DM, Nadjmi SS, Martha KE, Raihandhany R. 2026. Density and species diversity of mangrove flora in Leuweung Sancang Nature Reserve, Garut, West Java, Indonesia. Biodiversitas 27 (5): d270532. https://doi.org/10.13057/biodiv/d270532. Mangroves are an ecosystem of considerable ecological importance, situated in the coastal tidal zone and characterized by an overgrowth of plant species capable of surviving in inundated seawater zones. A comprehensive study of the Leuweung Sancang mangrove site reveals the presence of mangrove flora, though further study is necessary to describe the species diversity of this ecosystem fully. This study aimed to analyze the extent of mangroves, stand density, and floristic composition across seven mangrove blocks (Cibaluk, Cikabodasan, Cikolomberan, Cipalawah, Sakad, Cipunaga, and Cibako). Field surveys were conducted using block-based exploration combined with radius-based sampling, and voucher specimens were deposited in the Herbarium of Biology at Universitas Pendidikan Indonesia. Spatial boundaries were mapped using GPS-based KML conversion to GIS shapefiles. Species diversity was assessed using the Shannon-Wiener index (H′) and Pielou’s evenness (E), as well as the Sørensen-Dice similarity index and Non-metric Multidimensional Scaling ordination (NMDS) for differentiation among blocks. A total of 17 mangrove species across 10 families were recorded, with the Rhizophoraceae as the dominant family. Sonneratia alba showed the highest relative abundance (27%), followed by Rhizophora apiculata (19%) and Aegiceras corniculatum (13%). Total mangrove coverage reached 40.57 ha. Species diversity varied among blocks, with the highest value recorded in Cibako (H′ = 1.87), indicating moderate diversity, while other blocks showed lower values. Evenness values suggested uneven species distribution due to dominance by a few taxa. Similarity analysis and NMDS showed that Cipunaga, Cibako, Cipalawah and Sakad had similar species composition. The findings indicate that the biodiversity of mangrove species in the study area is suitable and supports the reproduction and development of mangrove plants. A comprehensive compilation of diversity data can serve as a crucial element in ecosystem management within conservation areas and support monitoring and future strategies by the Natural Resources Conservation Agency.
Abstract. Ansori AIR, Sabdono A, Subagiyo, Yusmalinda NLA, Pertiwi NPD, Apriliani LPC, Savitri NKRS, Sembiring A. 2026. Genetic diversity of Olive Ridley turtles (Lepidochelys olivacea) in West and North Lombok, Indonesia. Biodiversitas 27 (6): d270618. https://doi.org/10.13057/biodiv/d270618. The Olive Ridley turtle (Lepidochelys olivacea) is a globally distributed species playing a vital ecological role but remains classified as Vulnerable due to anthropogenic threats. This study investigates the genetic diversity and population structure of L. olivacea in West and North Lombok, Indonesia, using mitochondrial control region analysis. Previous genetic studies on this species in Indonesia have been limited to populations in Bali, making this the first report on Lombok populations. As the first genetic study of this species in Lombok, it aims to provide essential data to support evidence-based conservation and sustainable management strategies in the region. A total of 24 tissue samples were collected and analyzed with mitochondrial DNA in the control region (mtDNA CR) amplified using the PCR method, sequencing, and bioinformatic tools including Basic Local Alignment Search Tool (BLAST), Molecular Evolutionary Genetics Analysis version 11 (MEGA11), and DnaSP. All sequences showed high similarity (99.30%-100%) with L. olivacea reference sequences in GenBank. Phylogenetic analysis revealed that all samples clustered within the same global L. olivacea clade, consistent with conspecific classification. However, within this clade, the Lombok population exhibited notably low genetic diversity (Hd = 0.500) and moderate genetic structuring (FST = 0.27390), indicating limited gene flow and potential local isolation. These findings underscore the need for region-based conservation strategies that incorporate genetic data to maintain the adaptive potential and long-term viability of L. olivacea populations in Indonesia.
Abstract. Mistianah, Qomariyah IN, Widyaningrum DA, Budiono D, Hadiwijaya M, Fauzi A, Hastowohadi. 2026. Indigenous knowledge for biodiversity conservation and ecosystem protection by Tengger Tribe, East Java, Indonesia. Biodiversitas 27 (6): d270619. https://doi.org/10.13057/biodiv/d270619. Indigenous Ecological Knowledge (IEK) is a collection of environmental practices, beliefs, and knowledge that indigenous groups have created and passed down. Traditional conservation techniques are based on this profound understanding of biodiversity, including managing plants, animals, and ecosystems. However, because of insufficient documentation, much of this information is in danger of vanishing. This study aims to identify the Indigenous Ecological Knowledge of the Tengger Tribe in Tosari Village, Pasuruan District, East Java Province, Indonesia and to analyze the scientific knowledge embedded within their ecological practices. This study uses qualitative descriptive research with an ethnological approach to investigate the phenomena. The data collection techniques included semi-structured interviews with five key informants, questionnaires, field observations, and a literature review to gather data on the community’s ecological knowledge. The IEK was categorized based on practices related to water resource protection, plant utilization, agroforestry systems, and ritual and customary activities. The study documented 309 plant species used by the Tengger Tribe for rituals, medicine, and agroforestry. Meanwhile, the indigenous people successfully preserve ecosystem biodiversity, manage agroforestry areas, maintain ecosystem stability, and protect water resources. The Tengger Tribe’s indigenous ecological knowledge is vital for cultural preservation and environmental sustainability. Integrating this wisdom with modern sustainability approaches fosters holistic strategies, strengthens conservation efforts, and empowers Indigenous communities in global sustainability initiatives.
Abstract. Siahaan SJR, Afiati N, Helmi M. 2026. Habitat associations of Meretrix spp. in a mangrove coastal area of North Sumatra, Indonesia. Biodiversitas 27 (6): d270609. https://doi.org/10.13057/biodiv/d270609. The hard clams of the genus Meretrix are ecologically and economically important bivalves in tropical coastal ecosystems, yet information on their habitat associations in North Sumatra remains limited. This study examined the estimated density, spatial distribution, and habitat associations of Meretrix meretrix, M. lusoria, and M. astricta in the mangrove coastal area of Sei Nagalawan, Serdang Bedagai Regency, North Sumatra, Indonesia. Sampling was conducted at 30 intertidal stations during low tide. Sediment characteristics and water-quality variables were measured at each station to characterize local habitat conditions. Spatial patterns were visualized using GIS-based Spline interpolation, whereas Principal Component Analysis (PCA) was applied to summarize environmental gradients across the study area. A total of 517 molluscan individuals representing 12 taxa were recorded. Meretrix meretrix was the dominant species, accounting for 55.1% of the total abundance, followed by M. lusoria. The molluscan assemblage was characterized by low diversity (H′: 0.786), high evenness (E: 0.820), and moderate dominance (C: 0.516). Morisita’s index indicated clumped distribution patterns for all recorded Meretrix species. Estimated density ranged from 2 to 17 ind m⁻². PCA indicated that environmental variation among sampling stations was associated primarily with sediment texture and secondarily with water-quality conditions. Stations with higher Meretrix occurrence were generally associated with coarser sediments, whereas lower occurrences were recorded at stations containing higher proportions of fine sediments. Spatial interpolation revealed heterogeneous density patterns across the study area, with a root mean square error (RMSE) of 3.58. Differences in Meretrix occurrence among stations reflected variation in local habitat conditions across the study area. These findings provide baseline ecological information for future monitoring and management of mangrove-associated bivalve resources in North Sumatra, Indonesia.
Abstract. Rifai RM, Ameril C, Ramadani BMF, Annailah L, Yulistyorini A. 2026. Growth-response variation among selected coliform isolates under antibiotic stress in the Brantas River, East Java, Indonesia. Biodiversitas 27 (6): d270615. https://doi.org/10.13057/biodiv/d270615. Domestic wastewater inputs can influence microbial diversity and Anti-Microbial Resistance (AMR) in river systems. However, growth-response diversity among AMR-related coliform isolates remains poorly characterized. This is particularly relevant in the upper Brantas, where millions of people live in its watershed. Most previous assessments have focused on endpoint susceptibility profiles, while temporal growth responses under increasing antibiotic exposure remain less explored. In this study, coliform bacteria were isolated from a single densely populated riverbank site in the upper Brantas River. Selected isolates were tentatively identified as Escherichia coli, Klebsiella aerogenes, Klebsiella variicola, and Klebsiella pneumoniae. All Klebsiella isolates were resistant to amoxicillin, and K. aerogenes also showed resistance to tetracycline. We performed growth assays using antibiotic levels based on the Clinical and Laboratory Standards Institute (CLSI) breakpoints. Klebsiella aerogenes maintained growth up to 4× CLSI breakpoint. At the same time, K. variicola and K. pneumoniae grew more slowly and showed biphasic patterns, whereas E. coli was entirely suppressed. These findings remind us that even isolates from the same river site and with similar susceptibility classifications can respond differently when exposed to antibiotics. Growth-response profiling adds valuable insights beyond standard susceptibility tests and can help us better understand the phenotypic diversity within environmental AMR reservoirs. To deepen our understanding, future research should include larger collections of isolates, samples from multiple locations, and molecular studies to uncover the mechanisms behind these varied responses.
Abstract. Chandra AC, Maury HK, Ahmad I. 2026. A two-stage bait-trap method for collecting live subterranean termites under tropical field conditions. Biodiversitas 27 (6): d270612. https://doi.org/10.13057/biodiv/d270612. Obtaining sufficient numbers of live subterranean termites for laboratory-based research is a persistent methodological challenge. Conventional collection methods, including soil excavation, mound destruction, and log dismantling, are labor-intensive and destructive. This study introduces and evaluates a two-stage bait-trap method for collecting live subterranean termites from active colonies under tropical field conditions while minimizing disturbance to the substrate. In the first stage, wooden stakes were installed as bait stations to locate active termite foraging sites. In the second stage, sandwich (stacked-board) traps constructed from the same wood species were installed over infested stakes. Three locally available timber species, rubberwood (Hevea brasiliensis), acacia (Acacia mangium), and jabon (Anthocephalus cadamba) were used as bait materials, with 22 stakes per species evaluated during a three-month field trial, including one month of trap deployment. A total of 33 sandwich traps were installed following initial stake infestation; overall harvest success (initial termite encounter) was 70% (23 of 33), and active-capture success (live termites present at retrieval) was 48% of harvested traps (11 of 23). These two outcomes represent distinct endpoints: encounter and sustained live capture. Mean termite yield across all active traps was 944±854 individuals, including workers and soldiers. No statistically significant difference in termite counts was detected among wood species (F₂,₈: 0.74, p: 0.507; n: 11 active traps); the analysis was underpowered for detecting small-to-moderate effects. Three termite genera were recovered: Coptotermes, Microtermes, and Nasutitermes. The two-stage method successfully demonstrated live termite collection under tropical field conditions at the study site and offers a promising field protocol with potential applications in biodiversity surveys, ecological studies, and toxicological research that require live specimens. Further validation across additional sites and seasons is needed before the method can be considered broadly standardized.
Abstract. Masailla APD, Yuniastuti E, Parjanto. 2026. Chromosome karyotype analysis of Sapindus rarak (lerak) from Ungaran, Central Java, Indonesia. Biodiversitas 27 (6): d270620. https://doi.org/10.13057/biodiv/d270620. Sapindus rarak (lerak), a member of the family Sapindaceae and the soapberry group, has long been utilized as a natural cleaning agent due to its high saponin content. Despite its potential as an environmentally friendly and renewable resource, genetic information on this species remains limited. This study aimed to analyze the karyotype of S. rarak to provide fundamental cytogenetic data that can support plant breeding and conservation efforts. Two types of S. rarak, namely yellow and brown variants originating from Ungaran, Central Java, Indonesia, were used as research materials. Chromosome analysis was conducted using the squash preparation method, followed by microscopic observation and measurement of chromosome number, size, and centromere position. The data were analyzed descriptively to determine the karyotype characteristics. The results showed that both S. rarak types have the same chromosome number, 2n = 28, with chromosome sizes ranging from 0.856±0.145 to 2.487±0.222 µm. The karyotype formula was determined as 2n = 2x = 28 = 13m + 1sm, indicating a predominance of metacentric chromosomes. These findings provide essential baseline genetic information that can be used for species identification, support plant breeding programs, and contribute to the development of S. rarak as a sustainable, eco-friendly natural soap resource.
Abstract. Asrori I, Novarino W, Tjong DH, Flaggellata P, Zulfanedi Y, Roesma DI. 2026. Five microsatellite loci for preliminary kinship analysis and implications for conservation in Sumatran Tigers (Panthera tigris sumatrae). Biodiversitas 27 (5): d270533. https://doi.org/10.13057/biodiv/d270533. Microsatellite markers are widely used in wildlife pedigree analysis due to their high polymorphism and ability to assist in the determination of kinship relationships. Accurate pedigree information is crucial for effective population management and prevention of inbreeding in Sumatran tigers (Panthera tigris sumatrae), particularly in captive breeding programs. Fifteen microsatellite loci in the Felidae family were selected from previous studies and tested in 20 individuals, including six individuals with known kinship relationships, to identify informative and reliable markers for kinship analysis of Sumatran tigers. Amplification results showed that nine loci were consistently amplified in all samples with relatively high polymorphism. These loci were then evaluated for the number of alleles (Na), observed heterozygosity (Ho), polymorphic information content (PIC), amplification consistency, and genotyping error rate. Five loci showed consistent amplification and high levels of heterozygosity and polymorphism, with three loci (FCA279, FCA304, and FCA391) showing an error rate of 0.00, while two loci (FCA441 and 6HDZ700) had a lower error rate. Therefore, these five loci were selected as candidate markers for the Sumatran tiger pedigree analysis. Meanwhile, the other four loci (FCA008, 6HDZ463, 6HDZ170, and FCA220), although showing high Na, Ho, and He values, also had high error rates. Therefore, these four loci were excluded from further analysis. Cumulative probability of identity (PID) and PIDsibs estimates indicated that the selected panel of five loci had greater discriminatory power than only three loci. Kinship analysis using the selected loci yielded the expected relationships among known individuals, although the software's analysis model does not explicitly define parent-offspring relationships. Therefore, these results are preliminary and require further validation before broader application, given the limited sample size and incomplete representation of pedigree relationships.
Abstract. Marlina ET, Hidayati YA, Harlia E, Maulana YP, Puteri GCK. 2026. Isolation and cellulolytic activity of bacteria from beef cattle feces using rice straw as enrichment substrate. Biodiversitas 27 (6): d270617. https://doi.org/10.13057/biodiv/d270617. Beef cattle (Bos indicus/taurus) feces contain diverse microbial communities with potential roles in lignocellulosic biomass transformation. This study aimed to evaluate the initial decomposition of rice straw and beef cattle feces, using this information as a basis for isolating and preliminarily identifying cellulolytic bacteria from beef cattle waste. Rice straw was mixed with beef cattle feces to initiate decomposition for 7 days. Changes in chemical composition and structure were assessed using fiber fraction analysis and Scanning Electron Microscopy (SEM). The addition of cattle feces reduced Acid Detergent Fiber (ADF) from 51.36% to 42.31%, Neutral Detergent Fiber (NDF) from 72.08% to 60.82%, lignin from 12.89% to 7.40%, cellulose from 38.47% to 34.91%, and hemicellulose from 20.72% to 18.51%. SEM showed increased surface roughness and fiber degradation (loosening and fragmentation), with structural changes that can be attributed to microbial activity. Based on this finding, microbial enrichment was carried out with cattle feces and rice straw, with the addition of molasses as a nutrient source for microbial growth. Seven bacterial isolates were obtained, among which three (LS-6, LS-11 and LS-14) exhibited the highest cellulolytic activity on Carboxy-Methyl Cellulose (CMC) agar and dinitrosalicylic acid (DNS). Molecular level identification of these isolates through 16S rRNA gene sequence revealed that these isolates were closely affiliated with Bacillus safensis and Bacillus pumilus group. The results suggest that the isolates exhibit cellulolytic activity under the test conditions and may contribute to lignocellulose degradation. This study provides a first step for further research on cellulolytic bacteria from beef cattle feces for the effective use of lignocellulosic biomass.
Abstract. Pratiwi RH, Sunarti RN, Nurkanto A, Dasmo, Isfaeni H. 2026. Isolation, lytic activity, and genomic characterization of hospital wastewater phages infecting Mycobacterium smegmatis, a surrogate for tuberculosis bacteria. Biodiversitas 27 (6): d270613. https://doi.org/10.13057/biodiv/d270613. In Indonesia, Tuberculosis (TB) remains a major public health problem, with increasing case numbers and high mortality rates. The increasing prevalence of drug-resistant tuberculosis has encouraged exploration of bacteriophages as alternative antibacterial agents. This study aimed to isolate and characterize lytic bacteriophages from hospital wastewater capable of infecting Mycobacterium smegmatis, a surrogate host commonly used in tuberculosis-related research. Wastewater samples were collected from several hospital sewage outlets in Palembang and subjected to enrichment and plaque assay screening using M. smegmatis as the host bacterium. Three lytic bacteriophage isolates, designated HS, BR, and CH, were successfully obtained and characterized based on plaque morphology, phage titers, and lytic activity. All exhibited clear, small plaques (≈1.0 mm) characteristic of lytic morphology, with titers ranging from 2.3×10⁵ to 2.9×10⁵ PFU/mL. The lytic activity assay revealed that all phages significantly reduced bacterial growth within 10 hours. The CH phage achieved the highest inhibitory effect, reducing bacterial optical density (OD600) by 21%, compared to 14% reductions by HS and BR phages. Notably, CH phage-initiated lysis as early as the first hour, indicating a short latency period and strong infectivity. These results demonstrate that hospital wastewater is a promising source of mycobacteriophages with potential therapeutic value against mycobacterial infections. Among the isolates obtained, CH showed the most promising lytic performance and genomic characteristics, suggesting its potential for further investigation in bacteriophage-based strategies against mycobacterial infections. The WGS analysis demonstrates that the isolated bacteriophage represents a TehO-like phage lineage with high genomic similarity to several Pseudomonas bacteriophages. Genome analysis of the isolated bacteriophage revealed a modular genome organization characteristic of dsDNA bacteriophages, containing structural genes, DNA replication genes, and a lysis module encoding an endolysin.
Abstract. Wahyudi ANH, Ardyati T, Srihardyastutie A. 2026. Microbial diversity of bacterial cellulose starter culture revealed by 16S rRNA gene amplicon sequencing. Biodiversitas 27 (6): d270614. https://doi.org/10.13057/biodiv/d270614. Bacterial Cellulose (BC) is a biopolymer produced through microbial fermentation and widely applied in food, biomedical, and industrial fields. The performance of BC production is strongly influenced by the microbial composition of the starter culture. However, detailed information on the bacterial community structure of BC starter remains limited due to the constraints of culture-dependent methods. The aim of this research is to characterize the bacterial diversity and community composition of a BC starter culture using 16S rRNA gene amplicon sequencing and to complement the molecular data with culture-based enumeration. The starter culture was rejuvenated in coconut water medium and incubated at 30°C for 14 days. Cultivable bacteria capable of growing on Hestrin-Schramm medium were quantified using total plate count, yielding a population of (1.91±0.16) × 10⁹ CFU/mL. Amplicon sequencing analysis revealed a bacterial community with high richness but low evenness, characterized by strong taxonomic dominance. A total of 349 observed taxa were detected, with Firmicutes representing the dominant phylum (94.6%). At the genus level, Lentilactobacillus accounted for 86.9% of the relative abundance, while Lentilactobacillus parafarraginis was identified as the most abundant species (87%). These findings indicate that the BC starter culture analyzed in this research was dominated by lactic acid bacteria, particularly Lentilactobacillus. This pattern may suggest a possible role of Lentilactobacillus spp. in shaping the fermentation environment. The results provide a descriptive baseline for understanding the microbial ecology of BC starter culture to clarify the ecological significance of the dominant taxa.
