Antibiotic pollution in aquatic ecosystems and the growing demand for sustainable energy storage highlight the need for multifunctional materials with adjustable interfacial properties. This study developed silver (Ag)-modified g-C3N4 composites through a green method using palm oil mill effluent (POME) extract as a natural reducing agent. Structural and optical characterizations (FTIR, SEM-EDX, XRD, UV–Vis DRS, BET surface area) confirmed the incorporation of Ag nanoparticles, thereby reducing the bandgap from 2.80 to 2.30 eV and improving visible-light absorption. The 10% Ag/g-C3N4 photocatalyst showed efficient charge separation and interfacial electron transfer, achieving a maximum oxytetracycline (OTR) removal of 74.8% under simulated solar light. Process optimization using response surface methodology (Box–Behnken design) identified catalyst dose and solution pH as key factors, with optimal conditions (0.06 g catalyst, 14 ppm OTR, pH 12) producing performance in line with model predictions. Electrochemical tests further indicated that Ag addition enhanced the charge-storage capacity of g-C3N4, with the 8% Ag/g-C3N4 composite displaying the highest specific capacitance (43.59 mF g-1 at 2 mA) and energy density (6.05 μWh kg-1), along with the lowest charge-transfer resistance. This improvement is due to better electrical conductivity and ion transport at the Ag/g-C3N4 interface. In a textile-based supercapacitor, the 8% Ag composite with 1 M Na2SO4 hydrogel delivered superior performance (2.96 mF g-1, 0.411 μWh kg-1, and 128 μWh kg-1), showing enhanced redox activity and ion mobility. These results demonstrate that interfacial engineering of Ag/g-C3N4 is a promising approach for creating dual-functional materials for energy storage and environmental clean-up.

Sago processing waste stream, commonly called sago effluent, consists of a mixture of wet solid biomass and liquid hydrolysate. This industrial byproduct is rich in carbohydrates, particularly lignocellulosic materials, making it a promising feedstock for bioethanol production. In this study, sago effluent was subjected to physical pretreatment involving mechanical pulverisation and centrifugation to obtain a dense starch-rich wet biomass, termed total sago effluent concentrate (TSEC). The TSEC was subsequently used as a substrate for bioethanol production via fed-batch Simultaneous Saccharification and Fermentation (SSF), catalysed by amylolytic enzymes (alpha-amylase and glucoamylase) and Saccharomyces cerevisiae. SSF experiments were conducted in both non-buffered and citrate-buffered media, with buffer concentrations of 0, 25, 50and 100 mM. Maximum ethanol production was achieved in the non-buffered medium, with a concentration of 23.44 +/- 4.16 g/L and a theoretical ethanol yield (TEY) of 62.94 +/- 11.18%. No statistically significant differences were observed in ethanol production across the different buffered conditions. The highest ethanol concentration among the buffered systems was recorded at 23.22 +/- 2.44 g/L (62.33 +/- 6.57% TEY) in the 25 mM citrate buffer. This was followed by 20.67 +/- 2.85 g/L (55.33 +/- 4.80% TEY) in the 50 mM buffer and 20.61 +/- 1.79 g/L (55.33 +/- 4.82% TEY) in the 100 mM buffer. Overall, the findings demonstrate that TSEC is an effective and viable feedstock for bioethanol production using the fed-batch SSF process, with optimal performance observed in a non-buffered fermentation system

Aims: The aim of this study was to evaluate the antibacterial properties of a TiO2-SiO2/g-C3N4 nanocomposite synthesised using sol-gel and thermal polymerisation methods. Methodology and results: Field-Emission Scanning Electron Microscopy (FE-SEM) and Energy Dispersive X-ray (EDX) analyses were used to characterise the surface topology of the nanocomposite. The antibacterial efficacies of the synthesised TiO2-SiO2/g-C3N4 were assessed through agar well diffusion, disk diffusion, and broth macrodilution (minimum inhibitory concentration, MIC) assays. The test microorganisms included two bacterial species: Escherichia coli and Staphylococcus aureus. No visible zones of inhibition (ZOIs) were observed in either the agar well or disk diffusion assays, likely due to limited diffusion, poor solubility, and the short-lived nature of reactive oxygen species (ROS). However, MIC testing in liquid media revealed notable antibacterial activity, with MIC values of 0.25% for E. coli and 1.0% for S. aureus. This was further corroborated by SEM analysis, which revealed significant morphological damage in both bacterial species, underscoring the antibacterial potential of the TiO2-SiO2/g-C3N4 nanocomposite. Conclusion, significance and impact of study: Results suggest that TiO2-SiO2/g-C3N4 nanocomposite demonstrated effective antibacterial activity through ROS-mediated mechanisms, particularly under aqueous conditions that facilitate close contact with bacterial cells. These findings highlight its potential as a versatile agent for controlling bacterial contamination, especially in applications such as wastewater treatment, where moist environments enhance photocatalytic performance.

The development of visible-light-responsive, multifunctional photocatalysts is critical for advancing solid-state materials for environmental and antimicrobial applications. Conventional Ag/TiO2 photocatalytic systems offer a promising solution for visible-light responsiveness and antimicrobial properties, but often suffer from poor stability and recovery, as well as complex synthesis routes. In this work, a ternary Ag/Bi2MoO6/TiO2 (ABMOT) heterojunction photocatalyst was synthesized via a green, microwave-assisted approach using palm oil mill effluent (POME) as a natural reducing and stabilizing agent, thereby addressing waste valorization alongside material fabrication. Structural, morphological, and optical properties were systematically investigated using FTIR, XRD, PL, XPS, TEM, SEM-EDX, and UV-Vis DRS, thereby confirming the successful formation of a heterojunction and the enhancement of visible-light absorption. The ABMOT nanocomposite achieved 97.2% degradation of oxytetracycline under visible light irradiation at an optimal dosage of 0.6 g/L, attributed to its strong adsorption capacity, pollutant tolerance, and structural stability over four successive cycles. In addition, ABMOT imparted notable antibacterial activity against Escherichia coli and Staphylococcus aureus, demonstrating its multifunctional nature. To overcome the recovery limitations of slurry photocatalysts, ABMOT was immobilized in polyacrylonitrile (PAN) membranes via the phase inversion, resulting in improved hydrophilicity, porosity, water flux, and pollutant rejection. This study presents a sustainable approach to designing multifunctional ABMOT ternary photocatalysts with enhanced optical and physicochemical properties, providing insights into circular-economy-driven solid-state materials for advanced separation and photocatalytic technologies.

The extraction of sago starch generates substantial volumes of starch-rich wastewater, making the hydrolysate a potential substrate for bioethanol production. In this study, simultaneous saccharification and fermentation (SSF), using amylase and Saccharomyces cerevisiae, was conducted on sago effluent hydrolysate (SEH) to produce bioethanol. A commercial starch broth was used as the control to evaluate the efficacy of SEH as an alternative substrate. Both SEH and control exhibited comparable carbohydrate consumption profiles, with 91.70 % of total carbohydrates utilized from SEH, compared to 96.80 % in commercial starch. Ethanol production from SEH peaked at 8.39 g/l (78.02 % Theoretical Ethanol Yield, TEY) within 12 h, in comparison to 8.88 g/l, or 82.57 % TEY, for the commercial starch. However, statistical analyses confirmed that there was no significant difference between the ethanol yields of SEH and the commercial starch broth at the end of the fermentation period. These findings suggest that SEH is a viable and sustainable alternative feedstock for bioethanol production.

Fungi are widely distributed in agricultural settings, and certain species are known to cause infections that can impact public health and agricultural production. This study aims to determine the fungal concentration in the raw sago starch samples and to identify the fungal species in the samples. A total of 50 raw sago starch samples for commercialisation were collected from different districts in Sarawak, Malaysia. Enumeration of the fungal concentration was conducted using the serial dilution technique before identification of the fungal genera using morphological examinations. The fungal species were molecularly confirmed using species-specific polymerase chain reaction targeting the ITS region. The findings of this study found the range of fungal counts was 1.3 x 102 to 2.1 x 104 CFU/g (mean: 8.6 x 103 CFU/g). Morphological examinations followed by molecular confirmation revealed 19 fungal species, including Ceratocystis paradoxa (28.89%; 13/45), and followed by Paecilomyces variotii and Peniophora malaiensis (2.22%; 1/45 of each), Penicillium rolfsii and Pleurostoma richardsiae (8.89%; 4/ 45 of each), Perenniporia tephropora (4.44%; 2/45), Penicillium brasilianum, Penicillium sumatraense, Penicillium verruculosum, Penicillium citrinum, Paecilomyces niveus, Aspergillus sydowii, Aspergillus caesiellus, Aspergillus terreus, Trichoderma pleuroti, Trichoderma harzianum, Candida blattae, and Phaeoacremonium sp. (2.22%; 1/45 of each). All sago starch samples in this study were contaminated with diverse fungal species including mycotoxinproducing species, and the fungal counts exceeded the permissible limits for human consumption. The outcomes from this study provided a baseline on the level of fungal contamination in sago starch for future risk and mitigation assessment planning and established detailed knowledge of the food safety status in sago starch production from Sarawak, which will form a foundation for future studies.

The effect of an environmentally friendly green solvent template, ionic liquid (IL) - 1-butylimidazolium acetate on the surface area of TiO2 and its further combination with silver (Ag) dopant and cellulose acetate (CA) support were evaluated together. In this study, the TiO2/Ag/CA photocatalyst was synthesized and systematically investigated for the degradation of dyes. The incorporation of IL during synthesis led to a notable increase in the surface area of TiO2 (174.8 m2/g) and TiO2/Ag/CA (186.5 m2/g) photocatalyst, as evidenced by Brunauer Emmett Teller (BET) surface analysis. The findings revealed that TiO2/Ag/CA photocatalyst (IL: 3 mL, Ag: 2 wt%, CA: 0.5%) exhibited great efficiency in removing both individual and mixed dyes (MB, MO and RhB) under UV irradiation (lambda = 365 nm) and visible light (lambda = 440 nm) after 120 min. The antibacterial activity of TiO2-1/Ag 2%/CA 0.5% investigated via disc diffusion method against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) bacteria demonstrated inhibition zones, indicating the antibacterial effectiveness of the photocatalyst. With the imperative goal of eliminating chemical pollutants and undesired biological constituents from wastewater, the TiO2/Ag/CA photocatalyst investigated in this study exhibits the capability to effectively tackle both challenges with a high degree of efficiency.

The effect of an environmentally friendly green solvent template, ionic liquid (IL) - 1-butylimidazolium acetate on the surface area of TiO2 and its further combination with silver (Ag) dopant and cellulose acetate (CA) support were evaluated together. In this study, the TiO2/Ag/CA photocatalyst was synthesized and systematically investigated for the degradation of dyes. The incorporation of IL during synthesis led to a notable increase in the surface area of TiO2 (174.8 m2/g) and TiO2/Ag/CA (186.5 m2/g) photocatalyst, as evidenced by Brunauer Emmett Teller (BET) surface analysis. The findings revealed that TiO2/Ag/CA photocatalyst (IL: 3mL, Ag: 2wt%, CA: 0.5%) exhibited great efficiency in removing both individual and mixed dyes (MB, MO and RhB) under UV irradiation (λ = 365nm) and visible light (λ = 440nm) after 120min. The antibacterial activity of TiO2-1/Ag 2%/CA 0.5% investigated via disc diffusion method against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) bacteria demonstrated inhibition zones, indicating the antibacterial effectiveness of the photocatalyst. With the imperative goal of eliminating chemical pollutants and undesired biological constituents from wastewater, the TiO2/Ag/CA photocatalyst investigated in this study exhibits the capability to effectively tackle both challenges with a high degree of efficiency.

In the studies and production of bioethanol, the preferred fermenting yeast (Saccharomyces cerevisiae) is usually cultured in liquid broth that contains yeast extract and peptone. However, the use of these laboratory and scientific grade chemicals is costly, making them impractical for mass bioethanol production. Therefore, this study was conducted to evaluate the feasibility of glucose ethanolic fermentation by S. cerevisiae using generic fertiliser formulations to provide inorganic nitrogen, phosphorus, potassium and trace elements (NPK-TE). Fermentation media of different generic fertiliser strength at 0.5X, 1.0X and 2.0X Fertiliser Nitrogen Equivalents (FNE), as compared to the conventional Yeast Extract-Peptone (YEP) medium as control, was used as fermentation broth during the ethanolic fermentation of glucose. Based on the results, S. cerevisiae cultured in YEP broth produced the highest cell concentration for both wet (21.93 g/L) and dry cells (3.87 g/L), with rapid increment observed in the first 72 h of fermentation. By the end of the fermentation period, lactic acid (3.14 g/L) and acetic acid (0.96 g/L) levels were recorded to be the lowest in YEP medium while their concentration (lactic acid, 8.08 g/L) and (acetic acid, 2.67 g/L) were highest in 2.0X FNE fertiliser medium. Results indicated that the best theoretical ethanol yield (TEY) among the fertiliser media was achieved when fermentation was performed in the 0.5X FNE fertiliser medium, with a TEY of 86.18%. TEY yields were 78.68% and 51.54% in broth with 1.0X and 2.0X FNE, respectively. In general, all three fertiliser media supported ethanolic fermentation of glucose, with the 0.5X FNE fertiliser broth showing a yield that is significantly close to the conventional YEP medium, as seen in the statistical analysis. Similarities in other fermentation profiles such as acetic acid, lactic acid, and biomass production, as well as glucose utilisation, between the results from the YEP samples and samples from the fertiliser broths (at 0.5X and 1.0X FNE) have also shown that generic fertiliser has the potential to be used as an alternative medium to replace the conventional YEP to produce ethanol at a lower cost.

Purpose: Laccases are polyphenol oxidases that have diverse industrial applications. High industrial demand of laccases has necessitated the development of cost-effective production of recombinant laccases. One of the ways is by utilizing waste stream that has valuable composition for supporting microbial growth and metabolite expression. This work aims to intensify the production of recombinant laccases in Pichia pastoris GS115 using sago bioethanol liquid waste (SBLW) as a feedstock.Method: Production of laccases from SBLW was intensified by the addition of glycerol ranging from 0.5% - 2.5% (w/v). The fermentation performance was assessed based on the biomass concentration and laccase activity. The resulting laccases produced were further evaluated in terms of the capability of the enzyme to decolourise Remazol Brilliant Blue R dye.Results: The results showed that supplementation of SBLW with 2% (w/v) glycerol yielded improvements of 1.9-fold and 2.1-fold of biomass concentration and laccase activity, respectively in comparison to that achieved by fermentations using the standard Buffered Methanol-Complex Medium. Furthermore, the laccases produced using the optimal SBLW medium yielded a decolourisation percentage of 68.6% under non-optimised conditions and in the absence of mediators. The value represents 91% of the decolourising capability of laccases produced using the standard BMMH.Conclusion: In general, this works represents a further step towards low-cost production of recombinant laccases using renewable feedstocks.

Wood products are treated with wood preservatives to preserve and protect them from deterioration. Depending on the location of service, wood or wood-based products are usually exposed to different deterioration factors. Wood that serves outdoor, for example, will be frequently exposed to the effect of weathering with repeated hot and cold cycles which are prone to fungal degradation. In this chapter, we first give a brief explanation of the various factors that threaten the strength and rigidity of wood that necessitate its treatment with proper wood preservatives. Then we give an overview of the kind of wood preservation techniques that are available before moving on to some of the latest developments in the use of smart polymers as wood preservatives for wood protection. Smart polymer composites and their derivatives are attracting considerable attention as alternatives in wood protection and preservation because of their availability, nontoxicity, and compatibility toward the main wood components. With the increasing evidence on the potential of nanotechnology and bio-based materials such as chitosan, protein, and resins in wood preservation, it will be something to look forward to should there be a chance to combine nanotechnology with bio-based environmental friendly material for the making of smart polymers for wood preservation.

The use of waste stream generated upon the production of bioethanol from sago fibre has not been a major focus in the literature thus far. This study explores the feasibility of utilising the liquid waste generated following the production of bioethanol from sago fibre as a feedstock for the production of recombinant laccase in Pichia pastoris GS115. Characterisation of the sago bioethanol liquid waste (SBLW) indicated that glycerol was the main constituent along with glucose and lactic acid. Our results showed that P. pastoris GS115 growth was generally feasible when SBLW was used as a feedstock irrespective of its concentration.The expression of laccase reached the highest in fermentations that employed 40% (v/v) SBLW, whilst higher concentrations of SBLW resulted in the reduction of the laccase activity. The highest laccase activity achieved using 40% (v/v) SBLW represented 73% of that obtained using the standard synthetic medium. Further enhancement of maximum biomass concentration by 1.2-fold and laccase titre by 1.5-fold was achieved when the 40% (v/v) SBLW was supplemented with 1.0% (w/v) yeast extract. This work gives useful insights into the promising applications of SBLW as an inexpensive and sustainable feedstock for the production of industrial biocatalysts.

Industrial sago starch extraction from the sago palm (Metroxylon sagu) generates large volumes of wastewater, known as sago effluent that is generally discharged into nearby water bodies without proper treatment. This practice has led to severe environmental pollution that prompts the development of biotechnological treatments of sago effluent. In this study, Rhizopus oligosporus was grown in sago effluent at several initial pHs (pH 4, 5, and 6) during submerged fermentation to determine the optimum pH for high protein fungal biomass (HPFB) production while simultaneously reducing the starch content and high organic loads of sago effluent. Our results showed that the growth of R. oligosporus was the highest (3.8 g/L) when the initial pH of the sago effluent was 4. The same pH also gave the best reduction of starch, biochemical oxygen demand and chemical oxygen demand of the sago effluent following the R. oligosporus fermentations, which were 96.70%, 89.81%, and 78.30%, respectively. In addition, nitrate concentration was found to be reduced from 0.266 to 0.257 g/L, while the nitrite level dropped from 0.040 to 0.029 g/L. The present findings presented the potential of R. oligosporus for the production of HPFB as well as for treating sago effluent.

Abstract. Vincent M, Johnny Q, Adeni DSA, Suhaili N. 2020. Potential of Candida glabrata from ragi as a bioethanol producer using selected carbohydrate substrates. Nusantara Bioscience 12: 1-10. The flexibility and efficiency of fermenting microorganisms to convert substrates to ethanol are important factors in achieving high bioethanol yields during ethanolic fermentation. In this study, Candida glabrata, a common yeast found in fermented food, was evaluated in terms of its capability to produce ethanol using different types of carbohydrates, which included simple saccharides (glucose, maltose, sucrose), polysaccharides (starch and cellulose) and complex carbohydrates (total sago effluent, TSE). Our results indicated that C. glabrata was able to efficiently produce ethanol from glucose at 79.84% TEY (Theoretical Ethanol Yield). The ethanol production from sucrose was low, which was only 6.44% TEY, while no ethanol was produced from maltose. Meanwhile, for complex carbohydrate substrates such as starch and cellulose, ethanol was produced only when supplementary enzymes were introduced. Simultaneous Saccharification and Fermentation (SSF) of starch dosed with amylases resulted in an ethanol yield of 55.08% TEY, whilst SSF of cellulose dosed with cellulases yielded a TEY of 31.41%. When SSF was performed on TSE dosed with amylases and cellulases, the highest ethanol production was recorded within 24 h, with a yield of 23.36% TEY. Lactic acid and acetic acid were found to be at minimal levels throughout the fermentation period, indicating an efficient ethanol conversion. A notable increase in C. glabrata biomass was observed in cultures fed with glucose, starch (with supplementary amylases), and TSE (with supplementary amylases and cellulases). The current study indicates that C. glabrata can be used for bioethanol production from glucose, polysaccharides, and complex starchy lignocellulosic substrates such as TSE via SSF.

Aim This work reports a new method for the use of lasers for the selective killing of bacteria targeted using light-absorbing Silver nanoparticles (Ag-NPs) conjugated with a specific antibody against the Gram-positive bacterium Staphylococcus aureus (S. aureus). Methods and Results Ag-NPs were synthesized using a chemical reduction method and characterized with respect to their surface plasmon resonance, surface morphology via transmission electron microscopy (TEM) and dynamic light scattering (DLS). The bacterial surface was targeted using 20 nm Ag-NPs conjugated with an anti-protein A antibody. Labelled bacteria were irradiated with blue visible laser at 2 center dot 04 W/cm(2). The antibacterial activity of functionalized Ag-NPs was investigated by fluorescence microscopy after irradiation, and morphological changes in S. aureus after laser treatment were assessed using scanning electron microscopy (SEM). The laser-irradiated, functionalized Ag-NPs exhibited significant bactericidal activity, and laser-induced bacterial damage was observed after 10 min of laser irradiation against S. aureus. The fluorescence microscopic analysis results supported that bacterial cell death occurred in the presence of the functionalized Ag-NPs. Conclusions The results of this study suggest that a novel method for the preparation of functionalized nanoparticles has potential as a potent antibacterial agent for the selective killing of resistant disease-causing bacteria. Significance and Impact of the Study This study shows that Ag-NPs functionalized with a specific antibody, could be used in combination with laser radiation as a novel treatment to target resistant bacterial and fungal pathogens with minimal impact on normal microflora.

Aims: Oleaginous yeasts are widely used for the production of biodiesel feedstocks because of their high lipid content. This research was aimed to conduct random mutagenesis of Rhodotorula mucilaginosa using ethyl methane sulfonate (EMS) and identify the mutants with improved lipid production. Methodology and results: A total of twenty-two mutant isolates prescreened with cerulenin were produced and further characterized via M13 PCR fingerprinting to determine their polymorphism and genetic distances. Eight strains, namely M1, M2, M3, M4, M7, M10, M11 and M18, were chosen based on their genetic distances from the parental strain for biomass production. Six mutants (M1, M2, M3, M4, M7 and M18) showing the highest dry cell weights were further selected for evaluation of lipid production in a laboratory-scale bioreactor using glucose as a carbon source. Results indicated that parental strain exhibited lipid content of 1.83 g/L, while strains M1, M2, M3, M7 and M18 generated 2.37 g/L, 2.27 g/L, 2.27 g/L, 3.10 g/L and 3.83 g/L of intracellular lipid, respectively. These five mutants were identified to have significant increase in lipid production compared to the parental strain. Conclusion, significance and impact of study: This study demonstrated enhanced lipid production in R. mucilaginosa by random mutagenesis. New generated strains had higher lipid productivity compared to parental strain and application of these strains in industry may reduce the overall cost of biodiesel production.

Silver nanoparticles (Ag-NPs) possess excellent antibacterial properties and are considered to be an alternative material for treating antibiotic-resistant bacteria. The present study was aimed at enhancing the antibacterial efficiency of Ag-NPs using visible laser light against Escherichia coli and Staphylococcus aureus in vitro . Four concentrations of Ag-NPs (12.5, 25, 50, and 100 μ g/ml), synthesized by the chemical reduction method, were utilized to conduct the antibacterial activity of prepared Ag-NPs. The antibacterial efficiencies of photoactivated Ag-NPs against both bacteria were determined by survival assay after exposure to laser irradiation. The mechanism of interactions between Ag-NPs and the bacterial cell membranes was then evaluated via scanning electron microscopy (SEM) and reactive oxygen species analysis to study the cytotoxic action of photoactivated Ag-NPs against both bacterial species. Results showed that the laser-activated Ag-NP treatment reduced the surviving population to 14% of the control in the E. coli population, while the survival in the S. aureus population was reduced to 28% of the control upon 10 min exposure time at the concentration of 50 μ g/ml. However, S. aureus showed lower sensitivity after photoactivation compared to E. coli . Moreover, the effects depended on the concentration of Ag-NPs and exposure time to laser light. SEM images of treated bacterial cells indicated that substantial morphological changes occurred in cell membranes after treatment. The results suggested that Ag-NPs in the presence of visible light exhibit strong antibacterial activity which could be used to inactivate harmful and pathogenic microorganisms.

Huang CH, Adeni DSA, Johnny Q, Vincent M. 2018. Production of bioethanol from sago hampas via Simultaneous Saccharification and Fermentation (SSF). Nusantara Bioscience 10: 240-245. Sago hampas is an inexpensive, renewable and abundant agro-industrial residue that can be exploited to produce bioethanol. In this study, ethanol production was performed via simultaneous saccharification and fermentation (SSF) on fresh sago hampas at 2.5%, 5.0% and 7.5% (w/v) feedstock loadings with the aid of amylolytic enzymes, cellulolytic enzymes and Saccharomyces cerevisiae, under anaerobic condition for five days with a constant agitation of 150 rpm and ambient temperature. Results obtained indicated that SSF with 5.0% (w/v) sago hampas loading produced the highest ethanol yield at 17.79 g/L (79.65% Theoretical Ethanol Yield, TEY), while SSF using 2.5% and 7.5% (w/v) sago hampas produced ethanol at only 8.38 g/L (75.00% TEY) and 23.28 g/L (69.48% TEY), respectively. Total biomass reduction was recorded between 66.3% to 71.3% by the end of the SSF period. This study demonstrated that fresh sago hampas is a promising feedstock for bioethanol production as yields are generally high for all the substrate loadings tested. Moreover, bioethanol production using fresh sago hampas may assist in reducing pollution caused by sago waste accumulation.

Aims: Bacillus cereus is a Gram-positive, rod-shaped and spore-forming bacterium. It is a ubiquitous bacterium which is widely distributed in several environments such as soil and plants and is commonly isolated from food and its processing environment. This study was aimed to determine the genetic diversity and antibiotic resistance of B. cereus isolated from sago processing in Sarawak. Methodology and results: Out of 120 samples, 42 B. cereus isolates were detected with the presence of hly gene of B. cereus by using specific polymerase chain reaction (PCR). Twenty B. cereus isolates were randomly selected and further characterized by pulsed-field gel electrophoresis (PFGE) of chromosomal DNA digested with NotI to examine the genetic diversity. The result of the PFGE analysis confirmed that the B. cereus strains in sago processing were genetically diverse. Based on the dendrogram generated, B. cereus strains were grouped into two major clusters and these clusters were grouped together based on sources of isolation. The investigation on the antibiotic resistance of B. cereus strains revealed that the B. cereus strains were uniformly highly resistant to penicillin and ampicillin and highly susceptible to imipenem and norfloxacin. Conclusion, significance and impact of study: The results of this study suggest that the B. cereus isolated from sago processing derived from a mixture of sensitive and resistant strains with diverse genetic contents.

Vincent M, Hung MC, Baran PRM, Azahari AS, Adeni DSA. 2018. Isolation, identification and diversity of oleaginous yeasts from Kuching, Sarawak, Malaysia. Biodiversitas 19: 1266-1272. The present study was performed to isolate, identify and determine the diversity of oleaginous yeasts from various sources in Kuching, Sarawak (Malaysia). Microscopic observations via light and scanning electron microscope (SEM) indicated that the yeast isolates were in sizes ranging from 2-3 µm in width and 4-8 µm in length, typical of most unicellular ascomycotic fungi. Polymerase Chain Reaction (PCR) and molecular identification performed on the yeast isolates, targeting the D1/D2 region of the 26S rDNA, identified 6 yeast species from the 21 isolates, namely Pichia manshurica (5/21), Candida krusei (8/21), Candida parapsilosis (1/21), Pichia guilliermondii (2/21), Clavispora lusitaniae (1/21) and Kluyveromyces marxianus (4/21). All 21 yeast isolates accumulated intracellular lipids when grown in nitrogen-limited medium, as tested via Sudan IV staining. The present study is the first to document the production of lipids bodies in C. krusei, C. parapsilosis, and C. lusitaniae. Further investigations to assess the growth kinetics, lipid production efficiencies and lipids profiles of these oleaginous yeasts may provide insights into the possible utilization of these isolates for a variety of scientific, technical and industrial applications.