The effective management of waste cooking oil (WCO) presents a significant challenge in contemporary society. A promising approach to recycling WCO is its utilization as a substrate for the production of high-value compounds, such as prodigiosin, via microbial fermentation. Prodigiosin, primarily produced by Serratia marcescens, holds extensive applications as a natural red pigment in various domains. Nonetheless, suboptimal yields of prodigiosin can hinder its widespread adoption and indirectly impede the recycling of WCO. While mutagenesis stands as an effective strategy for augmenting prodigiosin yield, the dearth of rapid and efficient screening methods remains a significant challenge. In the present study, we established an efficient screening methodology by systematically investigating negative factors influencing prodigiosin production in Serratia marcescens La22. This approach enabled the identification of a high-yielding mutant, designated as Serratia sp. mf72, which exhibited a prodigiosin yield of 316 mg/mL, representing a notable 1.56-fold increase compared to the wild-type strain. Subsequent investigations revealed the potential of WCO as a cost-effective carbon source that synergistically enhanced prodigiosin production when combined with surfactants. Furthermore, the supplementation of precursors, including pyruvate, serine, proline, and arginine, derived from distinct prodigiosin biosynthetic pathways, led to a synergistic increase in prodigiosin yield. Ultimately, through the implementation of a meticulously optimized strategy incorporating fractional factorial design and response surface methodology, we achieved a prodigiosin yield of 1125 mg/L. This represented a substantial 5.43-fold enhancement in prodigiosin yield compared to the parental strain, underscoring the efficacy of the developed approach in maximizing prodigiosin production.

Hydrophilic phenol-formaldehyde (PF) foams, widely used in floral and hydroponic applications, are produced using phenol typically derived from non-renewable petroleum-based resources. This study examines the potential of depolymerized Kraft lignin (DKL) as a sustainable substitute for phenol in the synthesis of hydrophilic biobased foams. At 50 % DKL substitution, the foams demonstrated excellent water absorption capacities (up to 2557 %), relatively low densities (∼62 kg/m3), and nearly 100 % open-cell content. Its compressive strength (20.64 kPa at 10 % deformation) is comparable to commercially available floral and hydroponic foams. Additionally, foams with 10 % phenol substitution by DKL exhibited better thermal stability compared to neat phenolic foams. After 15 days of incubation with Laccase-producing bacterium Bacillus sp., 30 % and 50 % DKL foams exhibited the highest weight loss of 39.03 % and 38.9 %, respectively. Qualitative degree of biodegradation was further assessed using scanning electron microscopy and FT-IR analysis of the degraded samples.

Hydrogen sulfide (H2S) is a crucial signaling molecule in plants. Recent studies have shown that H2S plays an equally important role as nitric oxide (NO) and hydrogen peroxide (H2O2) in plant signaling. Previous studies have demonstrated the involvement of H2S in regulating drought and other stressful environmental conditions, but the exact downstream molecular mechanisms activated by the H2S signaling molecule remain unclear. In this study, we conducted a comprehensive genome-wide transcriptomic analysis of both wild type (WT) and double mutant (lcd/des1). Arabidopsis thaliana plants were exposed to 40% polyethylene glycol (PEG) to induce drought stress and 20 µM sodium hydrosulfide (NaHS). The resulting transcriptome data were analyzed for differentially significant genes and their statistical enrichments in the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. The results indicated significant upregulation of genes related to photosynthesis, carbon fixation, plant secondary metabolite biosynthesis, inositol and phosphatidylinositol signaling pathways, and stress-responsive pathways in mutant plants under drought stress. Mutant plants with impaired H2S signaling mechanisms displayed greater susceptibility to drought stress compared to wild-type plants. In summary, all findings highlight the pivotal role of H2S signaling in stimulating other drought-responsive signaling pathways.

Phenol formaldehyde foams, extensively utilized in wide range of applications face challenges due to depleting petroleum resources and adverse environmental concerns. This study explores a promising shift to biobased alternatives, specifically investigating the use of Kraft lignin (KL) by replacing about 10 to 50% phenol content to synthesize open-cell hydrophilic phenolic foams. The produced foams undergo comprehensive testing to evaluate wetting properties, porosity, mechanical strength, and biodegradation potential. Remarkably, foams with a high percentage of Kraft lignin exhibit outstanding physical and wetting characteristics. Notably, substituting 50% of phenol with KL gave rise to a foam with a density of 40 kg/m3, 3 , open cell porosity of about 100%, water absorption capacity of 2100%, and an average water uptake rate of 0.9 cm3/s. 3 /s. Furthermore, these lignin-substituted foams display enhanced biodegradability compared with their petroleum-based counterparts. The foam with the 40% phenol substitution exhibits the highest weight loss of approximately 68% in 15 days during the biodegradation test. The biodegradation was further confirmed using scanning electron microscopy and FT-IR analysis of the degraded samples.

Lead (Pb) and cadmium (Cd) have been identified as the primary contaminants in soil, posing potential health threats. This study aimed to examine the effects of applying a nitrogen fertilizer and a fungal agent Trichoderma harzianum J2 (nitrogen alone, fungi alone, and combined use) on the phytoremediation of soils co-contaminated with Pb and Cd. The growth of Leucaena leucocephala was monitored in the seedling, differentiation, and maturity stages to fully comprehend the remediation mechanisms. In the maturity stage, the biomass of L. leucocephala significantly increased by 18% and 29% under nitrogen-alone (NCK+) and fungal agent-alone treatments (J2), respectively, compared with the control in contaminated soil (CK+). The remediation factors of Pb and Cd with NCK+ treatment significantly increased by 50% and 125%, respectively, while those with J2 treatment increased by 73% and 145%, respectively. The partial least squares path model suggested that the nitrogen-related soil properties were prominent factors affecting phytoextraction compared with biotic factors (microbial diversity and plant growth). This model explained 2.56 of the variation in Cd concentration under J2 treatment, and 2.97 and 2.82 of the variation in Pb concentration under NCK+ and J2 treatments, respectively. The redundancy analysis showed that the samples under NCK+ and J2 treatments were clustered similarly in all growth stages. Also, Chytridiomycota, Mucoromucota, and Ciliophora were the key bioindicators for coping with heavy metals. Overall, a similar remediation mechanism allowed T. harzianum J2 to replace the nitrogen fertilizer to avoid secondary pollution. In addition, their combined use further increased the remediation efficiency.

Developing an efficient and continuous biomass saccharification system provides significant insight into sustainable energy. In the present work, a constant and effective bacterial saccharification system was developed to degrade wheat straw (WS) into sugars. Newly identified Bacillus altitudinis X-10 was selected to optimize sugar release from wheat straw via Box-Behnken Design (BBD). The released reducing sugars were 38.5 mg/g under the optimal fermentation conditions of pH 6.98, a temperature of 29.5 degrees C, and a solid-liquid ratio of 0.84%. In addition, B. altitudinis X-10 can produce low-cost enzyme cocktails, which contain remarkable xylanase activity (2.76 +/- 0.19 U/ml). The enzyme cocktail can break down untreated wheat straw biomasses and serve as a pretreatment to enhance the ability of cellulase to degrade wheat straw. The saccharification system can increase wheat straw digestibility, leading to a cost-effective and continuous bioconversion strategy for renewable energy and bio-based industries.

Most marine microalgae are typically cultivated in coastal areas due to challenges in inland cultivation. In this 185 days experiment, Nannochloropsis oceanica was semi-continuously cultivated inland using different photobioreactors (PBRs). The newly designed 700-liter (L) PBR exhibited tolerance to seasonal changes compared to the 150-L PBRs. The innovative in-situ oxygen release rate (ORR) measurement method results indicated that ORR was influenced by light intensity and temperature. The optimal temperature range for N. oceanica growth was 14-25 ℃, demonstrated cold tolerance and lipid accumulation at low temperatures. The maximum lipid content in 700-L and 150-L PBRs was 29 % and 28 %, respectively. Based on the average biomass productivity, the price of N. oceanica was $11.89 kg-1 (or $3.35 kg-1 based on maximum biomass productivity), which is cheaper than the current market price of $20.19 kg-1. From results, smaller PBRs at the same hydro electricity price are more cost-effective.

This paper summarizes the colonization dynamics of biofilms on microplastics (MPs) surfaces in aquatic environments, encompassing bacterial characteristics, environmental factors affecting biofilm formation, and matrix types and characteristics. The interaction between biofilm and MPs was also discussed. Through summarizing recent literatures, it was found that MPs surfaces offer numerous benefits to microorganisms, including nutrient enrichment and enhanced resistance to environmental stress. Biofilm colonization changes the surface physical and chemical properties as well as the transport behavior of MPs. At the same time, biofilms also play an important role in the fragmentation and degradation of MPs. In addition, we also investigated the coexistence level, adsorption mechanism, enrichment, and transformation of MPs by environmental pollutants mediated by biofilms. Moreover, an interesting aspect about the colonization of biofilms was discussed. Biofilm colonization not only had a great effect on the accumulation of heavy metals by MPs, but also affects the interaction between particles and environmental pollutants, thereby changing their toxic effects and increasing the difficulty of MPs treatment. Consequently, further attention and research are warranted to delve into the internal mechanisms, environmental risks, and the control of the coexistence of MPs and biofilms.

Greenhouse vegetable production aggravates soilborne diseases. Biochar has been recently considered as soil amendment to effectively prevent soilborne diseases. This study evaluates the immobilization and deactivation of pathogen-produced cell wall degrading enzymes (CWDEs) and toxic metabolites (TMs) by biochar to understand the mechanism involved in tomato Fusarium wilt, with activated carbon as the control. The results reveal that cellulase takes shorter time to reach the adsorption equilibrium than pectinase does. The adsorption isotherm of pectinase follows the Langmuir model, and the adsorption isotherm of cellulase follows the Freundlich model. The adsorption capacity of pectinase is greater than that of cellulase on biochar (on activated carbon). The adsorbed enzymes are completely immobilized and observably deactivated. The activity of immobilized pectinase decreases as 43.01 % of the original activity on biochar and 44.91 % on activated carbon. But the activity of immobilized cellulase decreases only as 1.88 % on biochar and 3.89 % on activated carbon. The tomato seedling bioassay analysis demonstrates that the adsorption of CWDEs and TMs is conducive to the reduction of disease severity. However, these established models (or laboratory simulation) cannot explain the enzyme adsorption process of biochar in the real soil, which requires the further exploration in the future.

Trimethylolpropane esters were synthesized from canola oil by a two-step transesterification-transesterification process. In the first step, canola oil is reacted with ethanol to produce canola oil ethyl ester, while in the second step, canola oil trimethylolpropane ester was obtained by reacting the canola oil ethyl ester and trimethylolpropane using K2CO3 as a catalyst. In the first step, under the optimal reaction conditions (70 & DEG;C, 2 h, ethanol-to-canola oil molar ratio of 10:1, and 0.25 wt.% catalyst loading), canola oil ethyl ester was successfully synthesized with a yield of 95.7 wt.%. In the second step, the final product with the maximum total concentration of canola oil trimethylolpropane ester (82%) and the maximum conversion of canola oil ethyl ester (85%) was obtained at 130 & DEG;C for 3 h with a canola oil ethyl ester to trimethylolpropane molar ratio of 3.1:1, and 1 wt.% loading of K2CO3 catalyst. The produced polyol esters can be a promising biolubricant with excellent lubricant characteristics, quenching performance, biodegradability, and rheological/tribological properties.

Lignocellulosic biomass is a prominent alternative raw material for producing valuable products via enzymatic hydrolysis. Lignocellulolytic enzymes are secreted by microorganisms (pure or mixed cultures of aerobic and anaerobic bacteria, yeasts and fungi, and algae), which can act synergistically to degrade biomass into fermentable sugars. However, inhibitory compounds and catabolic repression can inhibit the fermentation process. To overcome this issue, engineering strategies based on metabolic pathways, transcription factors, promoters, proteins, nanotechnology and division of labor have promoted modifying microbial gene expression, enhancing hydrolytic enzyme performance for lignocellulosic conversion. This chapter comprehensively discusses advances in approaches and engineered microorganism utilization for valorizing lignocellulose waste, along with possible opportunities in the bioeconomy.

Soil bacteria participate in self-immobilization processes for survival, persistence, and production of virulence factors in some niches or hosts through their capacities for autoaggregation, cell surface hydrophobicity, biofilm formation, and antibiotic and heavy metal resistance. This study investigated potential virulence, antibiotic and heavy metal resistance, solvent adhesion, and biofilm-forming capabilities of six cellulolytic bacteria isolated from soil samples: Paenarthrobacter sp. MKAL1, Hymenobacter sp. MKAL2, Mycobacterium sp. MKAL3, Stenotrophomonas sp. MKAL4, Chryseobacterium sp. MKAL5, and Bacillus sp. MKAL6. Strains were subjected to phenotypic methods, including heavy metal and antibiotic susceptibility and virulence factors (protease, lipase, capsule production, autoaggregation, hydrophobicity, and biofilm formation). The effect of ciprofloxacin was also investigated on bacterial susceptibility over time, cell membrane, and biofilm formation. Strains MKAL2, MKAL5, and MKAL6 exhibited protease and lipase activities, while only MKAL6 produced capsules. All strains were capable of aggregating, forming biofilm, and adhering to solvents. Strains tolerated high amounts of chromium, lead, zinc, nickel, and manganese and were resistant to lincomycin. Ciprofloxacin exhibited bactericidal activity against these strains. Although the phenotypic evaluation of virulence factors of bacteria can indicate their pathogenic nature, an in-depth genetic study of virulence, antibiotic and heavy metal resistance genes is required.

Coculture and whole-cell immobilization have myriad industrial applications for enhancing enzyme production. Using pretreated wheat straw as the sole carbon source, improving glucose isomerase production and cell growth by synthetic bacterial consortia was investigated. Thirteen cocultures were constructed based on the performance and antagonistic activities of monocultures from six cellulolytic soil bacteria. The performance of monocultures immobilized with calcium alginate was also tested. Only five cocultures (A, B, C, G and J) exhibited cell growth and enzyme production synergies. The highest level of synergism (15.17 U/mL) was found in coculture J composed of Mycobacterium sp. MKAL3 (4.06 U/mL) and Stenotrophomonas sp. MKAL4 (3.37 U/mL) with a synergism degree of 2.04. The synergism was unique to growth on wheat straw as it was completely absent in xylose-grown cocultures. The wheat straw degradation synergism could rely on specific compounds released by the MKAL3 strain that promote the activity of the MKAL4 strain and vice versa . However, immobilized strains MKAL1, MKAL2, MKAL3, MKAL4 and MKAL5 improved glucose isomerase production in the wheat straw fermentation process at different sodium alginate concentrations. Immobilization studies of purified glucose isomerases for hydrolysis and saccharification of wheat straw are now being conducted.

Forestry lignocellulosic waste is an important, largely untapped source of biomass for producing clean energy. In this study, a high-solids twin-screw extrusion approach is developed as a novel pretreatment method to effectively increase the biogas production rate to better fit commercial requirements. Multiple screw designs are progressively introduced with increasingly intensified mechanical shear. The experiments also looked at the impact of feed solids content and several cost-effective processing aids along with these screw designs. Various characterization methods were used to relate the physical state of the biomass based on its specific surface area and volatile fraction, to the rate of biomethane generation possible from a 14- and 31-day biomethane potential test. An increase in biomethane production over this period by up to 190% was possible with the optimal screw design compared to a benchmark sample. This is a promising finding for the industrialization of biomethane production from forestry lignocellulosic biomass.

The demand for enzymes is increasing continuously due to their applications in various avenues. The pectin-hydrolyzing bacteria, Cellulomonas sp. and Bacillus sp., isolated from forest soil have the potential to produce industrially important enzymes (pectinase, PGase, Cellulase, and xylanase). However, these bacteria have different optimal cultural conditions for pectinase production. The optimal cultural conditions for Cellulomonas sp. were room temperature (25–26℃), pH 7, 1% inoculum volume, and 1.5% citrus pectin with 8.82 ± 0.92 U/mL pectinase activity. And Bacillus sp. illustrated the highest pectinase activity (12.35 ± 0.72 U/mL) at room temperature, pH 10, 1% inoculum volume, and 1.5% pectin concentration. Among the different agro-wastes, the orange peel was found to be the best substrate for pectinase, PGase, and cellulase activity whereas barley straw for xylanase activity. Further, Cellulomonas sp. and Bacillus sp. illustrated higher pectinase activity from commercial pectin compared to orange peel showing their preference for commercial citrus pectin. In addition, the optimization by the Box-Behnken design increased pectinase activity for Cellulomonas sp., while a noticeable increase in activity was not observed in Bacillus sp. Besides, all the agro-wastes exploited in this study can be used for pectinase, PGase, and xylanase production but not cellulase. The study revealed that each bacteria has its specific optimal conditions and there is a variation in the capacity of utilizing the various lignocellulosic biomass.

Modern society has a great challenge to decrease waste and minimize the adverse effects of wastes on the economy, environment, and individual health. Thus, this study focuses on the use of eight agro-wastes (banana peel, barley straw, canola straw, pomegranate peel, orange peel, pumpkin pulp+seeds, maple leaf, and brewer's spent grains) by a novel bacterium (Streptomyces thermocarboxydus) for enzymes production. Further, the study explored the subsequent degradation of those wastes by the bacterium. This bacterium was isolated from forest soil and identified as Streptomyces thermocarboxydus by 16S rRNA sequence analysis. The biodegrading capability of S. thermocarboxydus was determined by observing the clear zone around the colony cultured on the agar plate containing the different biomasses as sole carbon sources and calculating the substrate degradation ratios. Furthermore, scanning electron microscopy images of eight agro-wastes before and after bacterial treatment and weight loss of agro-wastes revealed the bacterium degraded the biomasses. The different trends of enzyme activities were observed for various wastes, and the maximum activity depended on the type of agro-wastes. Overall, S. thermocarboxydus was found to be a potential candidate for pectinase and xylanase production. The enzyme production varies with the concentration of the biomasses.

The present work demonstrated the potential of different agro-waste mixtures to produce ethanol. The forest soil bacterium (Streptomyces sp.) was exploited for the saccharification of the agro-waste mixture formulated by extreme vertices mixture design and the hydrolysate produced by saccharification was used for fermentation. The best formulation contained 43.33% orange peel, 33.33 % pumpkin pulp+seeds, and 23.33% pomegranate peel which exhibited significantly high reducing sugar (22.36±0.54 mg/g dry weight) among all other mixtures. The hydrolysate of this mixture when supplemented with 2% w/v fructose produced a maximum of 7.86±0.08% v/v ethanol by the yeast isolated from the brewer's spent grains. Thus, easily available waste could be a promising source for yeast isolation and feedstock for ethanol production. Further, this study aids to reduce the risk of health, and environmental pollution, and developing the economy.

Microplastics have become a global environmental concern due to their ubiquitous presence and persistence in the environment and have been identified as a major pollutant in aquatic environments. This study aimed to evaluate the effect of various concentrations of polyethylene terephthalate (PET) microplastic (25–200 mg/L) on the growth, chlorophyll content, and toxicity of Scenedesmus sp. from aquatic and terrestrial habitats over a period of 24 days. Our results showed that microplastics with higher concentration (200 mg/L) have a significantly higher inhibitory effect. Also, higher concentration of extracellular hydrogen peroxide (H2O2) extracellular polymeric substance (EPS) were found on microalgae exposed to the microplastic. Further, Scanning Electron Microscope (SEM) images revealed that microalgae attached to microplastic surfaces and formed hetero-aggregation. Overall, our study provided valuable information for understanding the complex effects of microplastics on microalgae, particularly in comparing the differential effects on aquatic and terrestrial Scenedesmus sp.

Pectinase is a prominent industrial enzyme with a high market demand and huge applications in diverse avenues. There are different sources for pectinase production; however, a highly stable microbial pectinase that can withstand different physiochemical conditions is needed. Therefore, this study explored the thermostability of the pectinase protein cloned and expressed in Escherichia coli BL21(DE3) from two forest soil bacteria (S-5 and S-14) identified as Streptomyces sp. The pectinase gene illustrated about 750 bp on the gel after electrophoresis and encoded a product of approximately 25 kDa molecular weight. Both expressed pectinase proteins showed optimal activity at 2 different pHs (pH 5 and 9) and 50 degrees C. When both recombinant pectinases were exposed to different temperatures, they were able to retain their activity for 120 min indicating both have important thermostable properties. These enzymes could have great potential in industrial biotechnological processes due to their stability over broad pH and high temperatures.

Glucose isomerase (GI) is an enzyme with high potential applications. Characterization of GI producing bacteria with interesting properties from an industrial point of view is essential. Bacillus sp., Paenarthrobacter sp., Chryseobacterium sp., Hymenobacter sp., Mycobacterium sp., and Stenotrophomonas sp. were isolated from soil samples. Optimization of enzyme production yield was investigated in various fermentation conditions using response surface methodology. All isolates exhibited maximum GI activity at 40 °C, pH 6–8 after 4 days of incubation. A mixture of peptone/yeast extract or tryptone/peptone enhanced higher enzyme production. The same trend was observed in fermentation medium containing 1% xylose or 2%–2.5% wheat straw. This study advanced the knowledge of these bacterial isolates in promoting wheat straw as feedstock for the bio-based industry.