Modulating the pH profile of vanillin dehydrogenase enzyme from extremophile Bacillus ligniniphilus L1 through computational guided site-directed mutagenesis.

Vanillin dehydrogenase (VDH) has recently come forward as an important enzyme for the commercial production of vanillic acid from vanillin in a one-step enzymatic process. However, VDH with high alkaline tolerance and efficiency is desirable to meet the biorefinery requirements. In this study, computationally guided site-directed mutagenesis was performed by increasing the positive and negative charges on the surface and near the active site of the VDH from the alkaliphilic marine bacterium Bacillus ligniniphilus L1, respectively. In total, 20 residues including 15 from surface amino acids and 5 near active sites were selected based on computational analysis and were subjected to site-directed mutations. The optimum pH of the two screened mutants including I132R, and T235E from surface residue and near active site mutant was shifted to 9, and 8.6, with a 2.82- and 2.95-fold increase in their activity compared to wild enzyme at pH 9, respectively. A double mutant containing both these mutations i.e., I132R/T235E was produced which showed a shift in optimum pH of VDH from 7.4 to 9, with an increase of 74.91 % in enzyme activity. Therefore, the double mutant of VDH from the L1 strain (I132R/T235E) produced in this study represents a potential candidate for industrial applications.

Surface display system of Bacillus subtilis: A promising approach for improving the stability and applications of cellobiose dehydrogenase.

Cellobiose dehydrogenase (CDH) plays a crucial role in lignocellulose degradation and bioelectrochemical industries, making it highly in demand. However, the production and purification of CDH through fungal heterologous expression methods is time-consuming, costly, and challenging. In this study, we successfully displayed Pycnoporus sanguineus CDH (psCDH) on the surface of Bacillus subtilis spores for the first time. Enzymatic characterization revealed that spore surface display enhanced the tolerance of psCDH to high temperature (80 °C) and low pH levels (3.5) compared to free psCDH. Furthermore, we found that glycerol, lactic acid, and malic acid promoted the activity of immobilized spore-displayed psCDH; glycerol has a more significant stimulating effect, increasing the activity from 16.86 ± 1.27 U/mL to 46.26 ± 3.25 U/mL. After four reuse cycles, the psCDH immobilized with spores retained 48% of its initial activity, demonstrating a substantial recovery rate. In conclusion, the spore display system, relying on cotG, enables the expression and immobilization of CDH while enhancing its resistance to adverse conditions. This system demonstrates efficient enzyme recovery and reuse. This approach provides a novel method and strategy for the immobilization and stability enhancement of CDH.

Harnessing the power of bacterial laccases for xenobiotic degradation in water: A 10-year overview.

Industrialization and population growth are leading to the production of significant amounts of sewage containing hazardous xenobiotic compounds. These compounds pose a threat to human and animal health, as well as the overall ecosystem. To combat this issue, chemical, physical, and biological techniques have been used to remove these contaminants from water bodies affected by human activity. Biotechnological methods have proven effective in utilizing microorganisms and enzymes, particularly laccases, to address this problem. Laccases possess versatile enzymatic characteristics and have shown promise in degrading different xenobiotic compounds found in municipal, industrial, and medical wastewater. Both free enzymes and crude enzyme extracts have demonstrated success in the biotransformation of these compounds. Despite these advancements, the widespread use of laccases for bioremediation and wastewater treatment faces challenges due to the complex composition, high salt concentration, and extreme pH often present in contaminated media. These factors negatively impact protein stability, recovery, and recycling processes, hindering their large-scale application. These issues can be addressed by focusing on large-scale production, resolving operation problems, and utilizing cutting-edge genetic and protein engineering techniques. Additionally, finding novel sources of laccases, understanding their biochemical properties, enhancing their catalytic activity and thermostability, and improving their production processes are crucial steps towards overcoming these limitations. By doing so, enzyme-based biological degradation processes can be improved, resulting in more efficient removal of xenobiotics from water systems. This review summarizes the latest research on bacterial laccases over the past decade. It covers the advancements in identifying their structures, characterizing their biochemical properties, exploring their modes of action, and discovering their potential applications in the biotransformation and bioremediation of xenobiotic pollutants commonly present in water sources.

Display of Lignin Peroxidase on the Surface of Bacillus subtilis.

Lignin peroxidase (LiP) has a good application prospect in lignin degradation, environmental treatment, straw feed, and other industries. However, its application is constrained by the high price and low stability of enzyme preparation. In this study, the Escherichia coli-Bacillus subtilis (E. coli-B. subtilis) shuttle expression vector pHS-cotG-lip was constructed and displayed on the surface of Bacillus subtilis spores. The analysis of enzymatic properties showed that the optimal catalytic temperature and pH of the immobilized LiP were 55 °C and 4.5, respectively. Compared with free LiP (42 °C and pH4.0), the optimal reaction temperature increased by 13 °C. After incubation at 70 °C for 1 h, its activity remained above 30%, while the free LiP completely lost its activity under the same conditions. Adding Mn2+, DL-lactic acid, and PEG-4000 increased the CotG-LiP enzyme activity to 313%, 146%, and 265%, respectively. The recyclability of spore display made the fusion protein CotG-LiP retain more than 50% enzyme activity after four cycles. The excellent recycling rate indicated that LiP displayed on the spore surface had a good application prospect in sewage treatment and other fields, and also provided a reference for the rapid and low-cost immobilized production of enzyme preparations.

Lignin developmental patterns and Casparian strip as apoplastic barriers: A review.

Lignin and Casparian strips are two essential components of plant cells that play critical roles in plant development regulate nutrients and water across the plants cell. Recent studies have extensively investigated lignin diversity and Casparian strip formation, providing valuable insights into plant physiology. This review presents the established lignin biosynthesis pathway, as well as the developmental patterns of lignin and Casparian strip and transcriptional network associated with Casparian strip formation. It describes the biochemical and genetic mechanisms that regulate lignin biosynthesis and deposition in different plants cell types and tissues. Additionally, the review highlights recent studies that have uncovered novel lignin biosynthesis genes and enzymatic pathways, expanding our understanding of lignin diversity. This review also discusses the developmental patterns of Casparian strip in roots and their role in regulating nutrient and water transport, focusing on recent genetic and molecular studies that have identified regulators of Casparian strip formation. Previous research has shown that lignin biosynthesis genes also play a role in Casparian strip formation, suggesting that these processes are interconnected. In conclusion, this comprehensive overview provides insights into the developmental patterns of lignin diversity and Casparian strip as apoplastic barriers. It also identifies future research directions, including the functional characterization of novel lignin biosynthesis genes and the identification of additional regulators of Casparian strip formation. Overall, this review enhances our understanding of the complex and interconnected processes that drive plant growth, pathogen defense, regulation and development.

Synthesis of novel metal silica nanoparticles exhibiting antimicrobial potential and applications to combat periodontitis.

Periodontitis is a severe form of gum disease caused by bacterial plaque that affects millions of people and has substantial worldwide health and economic implications. However, current clinical antiseptic and antimicrobial drug therapies are insufficient because they frequently have numerous side effects and contribute to widespread bacterial resistance. Recently, nanotechnology has shown promise in the synthesis of novel periodontal therapeutic materials. Nanoparticles are quickly replacing antibiotics in the treatment of bacterial infections, and their potential application in dentistry is immense. The alarming increases in antimicrobial resistance further emphasize the importance of exploring and utilizing nanotechnology in the fight against tooth diseases particularly periodontitis. We developed 16 different combinations of mesoporous silica nanomaterials in this study by ageing, drying, and calcining them with 11 different metals including silver, zinc, copper, gold, palladium, ruthenium, platinum, nickel, cerium, aluminium, and zirconium. The antibacterial properties of metal-doped silica were evaluated using four distinct susceptibility tests. The agar well diffusion antibacterial activity test, which measured the susceptibility of the microbes being tested, as well as the antibacterial efficacy of mesoporous silica with different silica/metal ratios, were among these studies. The growth kinetics experiment was used to investigate the efficacy of various metal-doped silica nanoparticles on microbial growth. To detect growth inhibitory effects, the colony-forming unit assay was used. Finally, MIC and MBC tests were performed to observe the inhibition of microbial biofilm formation. Our findings show that silver- and zinc-doped silica nanoparticles synthesized using the sol-gel method can be effective antimicrobial agents against periodontitis-causing microbes. This study represents the pioneering work reporting the antimicrobial properties of metal-loaded TUD-1 mesoporous silica, which could be useful in the fight against other infectious diseases too.

Immediate health risk: Concentration of heavy metals in contaminated freshwater fishes from the river channel of Turag-Tongi-Balu.

The consumption of contaminated finfish from the polluted river channel of Turag-Tongi-Balu, Kamarpara site, Dhaka poses significant health hazards to humans. We used mass spectrometry on chemically digested liquid samples from five fish species from Turag-Tongi-Balu to estimate the concentrations of 10 elements (Cr, Mn, Ni, Cu, Zn, As, Se, Cd, Fe, and Pb). Except M. vittatus, the mean concentrations of Cd, Mn, Pb, and Se exceeded the Food Safety Guideline (FSG) value in all fish species. Among the species studied, L. rohita, C. punctata, C. batrachus, H. fossilis, and M. vittatus exhibited higher Mn concentrations surpassing the FSG threshold, thus elevating the non-carcinogenic risk across all species. There were statistically significant differences (p < .05) in the mean concentrations of heavy metals among fish species. The Target Hazard Quotient (THQ) value of Mn poses a significant non-carcinogenic risk to human health, while the hazard of other metals is negligible. Except for M. vittus, the Hazard Index value (HI ≥ 1) revealed the risk that all metals exceed the limit and pose a threat to human health. Cd, As, and Ni metals pose a significant carcinogenic risk to human health from the consumption of fish samples, which is a particularly alarming target cancer risk (TCR). In conclusion, regular dietary consumption of fish from this polluted ecosystem of the Turag-Tongi-Balu River channel's Kamarpara site poses a significant health risk and is indicated as cancer. This study emphasizes the significance of monitoring heavy metal contamination in finfish and minimizing the risk to human health with effective measures.

Fermentation, functional analysis, and biological activities of turmeric kombucha.

BACKGROUND: Kombucha is a popular fermented drink with therapeutic benefits. The present study aimed to examine the fermentation of turmeric-infused kombucha and evaluate its biological activities and functional properties. RESULTS: The study of pH dynamics during fermentation found that turmeric kombucha has a lower pH decrease than standard kombucha, with the lowest pH of 3.1 being observed in 0.1% turmeric kombucha and the maximum pH of 3.8 found in 1% turmeric kombucha. The research shows that the symbiotic consortia of bacteria and yeast alters during the fermentation process with turmeric. Gas chromatogrphy-mass spectrometry analysis revealed that turmeric kombucha is abundant in terpenes, ketones, alcohols, aldehydes, phenols and fatty acids, with higher levels of active ingredients than regular kombucha. The kombucha with 0.6% turmeric had the highest overall acceptance score (9.0) in sensory evaluation. The total phenolic content after fermentation was in the range 0.2-0.8 mg gallic acid equivalents mL-1 . Increasing turmeric concentrations increased the antioxidant, cytotoxic and antibacterial activity of kombucha analogs, with the highest antioxidant activity (89%) observed at 0.8% turmeric, and the maximum cytotoxicity (74%) and antibacterial activity (zones of inhibition of 17.7 and 15.9 mm against Staphylococcus aureus and Escherichia coli, respectively) observed at 1% turmeric. CONCLUSION: The fermentation of kombucha infused with turmeric enhanced its biological activities, making it a healthier alternative to traditional kombucha and presenting new opportunities in the field of functional foods. Further investigations into the mechanisms underlying these effects and in vivo studies are warranted to fully comprehend the impact of turmeric kombucha consumption on human health. © 2023 Society of Chemical Industry.

Laccase and dye-decolorizing peroxidase-modified lignin incorporated with keratin-based biodegradable film: An elucidation of structural characterization, antibacterial and antioxidant properties.

Lignin valorization to produce functionalized materials is challenging. This study harnessed the versatile properties of lignin through a grafting reaction involving the aryl hydroxyl group of alkali lignin (AL) and enzymatically modified-alkali lignin (EMAL) using Bacillus ligninphilus-derived laccase (Lacc) L1 and C. seriivinvornas-derived dye-decolorizing peroxidase (DyP) with keratin (K) amide group. This reaction was executed utilizing an eco-friendly solvent with the aim of generating thin films. A thorough investigation was conducted, focusing on grafting AL and EMAL onto K. The incorporation of EMAL into the films enhanced tensile strength (TS) (14.8±1.8 MPa) and elongation at break (EAB) (23.7±0.3 %). Additionally, it enhanced thermal stability, suppressed the proliferation of Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli), and mitigated oxidative stress. This study introduces a novel approach for lignin valorization, offering the potential to tailor mechanical properties, antibacterial and antioxidant properties of the final material, making it sustainable substitute for petroleum-based products.

Ectoine Globally Hypomethylates DNA in Skin Cells and Suppresses Cancer Proliferation.

Epigenetic modifications, mainly aberrant DNA methylation, have been shown to silence the expression of genes involved in epigenetic diseases, including cancer suppression genes. Almost all conventional cancer therapeutic agents, such as the DNA hypomethylation drug 5-aza-2-deoxycytidine, have insurmountable side effects. To investigate the role of the well-known DNA protectant (ectoine) in skin cell DNA methylation and cancer cell proliferation, comprehensive methylome sequence analysis, 5-methyl cytosine (5mC) analysis, proliferation and tumorigenicity assays, and DNA epigenetic modifications-related gene analysis were performed. The results showed that extended ectoine treatment globally hypomethylated DNA in skin cells, especially in the CpG island (CGIs) element, and 5mC percentage was significantly reduced. Moreover, ectoine mildly inhibited skin cell proliferation and did not induce tumorigenicity in HaCaT cells injected into athymic nude mice. HaCaT cells treated with ectoine for 24 weeks modulated the mRNA expression levels of Dnmt1, Dnmt3a, Dnmt3b, Dnmt3l, Hdac1, Hdac2, Kdm3a, Mettl3, Mettl14, Snrpn, and Mest. Overall, ectoine mildly demethylates DNA in skin cells, modulates the expression of epigenetic modification-related genes, and reduces cell proliferation. This evidence suggests that ectoine is a potential anti-aging agent that prevents DNA hypermethylation and subsequently activates cancer-suppressing genes.

Metagenomic investigations on antibiotic resistance and microbial virulence in oil-polluted soils from China.

Engine oil spills have been associated with a wide range of human health problems. However, little is known about the effects of petroleum hydrocarbon pollution on soil microbial communities. In this study, three samples were collected from oil-polluted soils (OPS), and one control soil (CS) from Taolin town, China, near the old engine's scrapes was used. The aims of this study were to conduct metagenomic sequencing and subsequently perform resistome and virulome analysis. We also aimed to validate anti-microbial resistance and virulence genes and anti-bacterial sensitivity profiles among the isolates from oil-polluted soils. The OPS microbial community was dominated by bacterial species compared to the control samples which were dominated by metazoans and other organisms. Secondly, the resistosome and virulome analysis showed that ARGs and virulence factors were higher among OPS microbial communities. Antibiotic susceptibility assay and qPCR analysis for ARGs and virulence factors showed that the oil-polluted soil samples had remarkably enhanced expression of these ARGs and some virulence genes. Our study suggests that oil pollution contributes to shifting microbial communities to more resilient types that could survive the toxicity of oil pollution and subsequently become more resilient in terms of higher resistance and virulence potential.

Strategies for efficient management of microplastics to achieve life cycle assessment and circular economy.

The anticipated increase in the influx of plastic waste into aquatic environments has propelled the identification and elimination of plastic waste into the global agenda. The plastics sector generates a significant volume of materials, which, due to their extended durability, accumulate rapidly in natural ecosystems. Consequently, this indiscriminate utilization, along with the deposition of plastic waste (PW) in landfills and inadequate recycling practices, leads to diverse economic, social, and environmental consequences. Microplastics (MPs) are a type of PW that has been fragmented into particles measuring less than 5 mm. These particles have been found in several environments, including the air, soil, freshwater, and ocean ecosystems, where they accumulate in large quantities. In order to gain insight into the ecological risks and resource implications associated with a plastic product, it is strongly advised to conduct life cycle and sustainability analyses. Therefore, this paper examines various strategies aimed at achieving effective management of MP waste in order to develop a conceptual framework for MPs in circular economy and life cycle assessment (LCA). The findings of this study provides a new avenue for future research and contribution to manage MP waste as well as reduce their environmentally hazardous impact.

Evaluation of a dye-decolorizing peroxidase from Comamonas serinivorans for lignin valorization potentials.

Although dye-decolourising peroxidases (DyPs) are well-known for lignin degradation, a comprehensive understanding of their mechanism remains unclear. Therefore, studying the mechanism of lignin degradation by DyPs is necessary for industrial applications and enzyme engineering. In this study, a dye-decolourising peroxidase (CsDyP) gene from C. serinivorans was heterologously expressed and studied for its lignin degradation potential. Molecular docking analysis predicted the binding of 2, 2-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), veratryl alcohol (VA), 2, 6-dimethylphenol (2, 6- DMP), guaiacol (GUA), and lignin to the substrate-binding pocket of CsDyP. Evaluation of the enzymatic properties showed that CsDyP requires pH 4.0 and 30 °C for optimal activity and has a high affinity for ABTS. In addition, CsDyP is stable over a wide range of temperatures and pH and can tolerate 5.0 mM organic solvents. Low NaCl concentrations promoted CsDyP activity. Further, CsDyP significantly reduced the chemical oxygen demand decolourised alkali lignin (AL) and milled wood lignin (MWL). CsDyP targets the ß-O-4, CO, and CC bonds linking lignin's G, S, and H units to depolymerize and produce aromatic compounds. Overall, this study delivers valuable insights into the lignin degradation mechanism of CsDyP, which can benefit its industrial applications and lignin valorization.

Genomic and biotechnological potential of a novel oil-degrading strain Enterobacter kobei DH7 isolated from petroleum-contaminated soil.

In this study, a novel oil-degrading strain Enterobacter kobei DH7 was isolated from petroleum-contaminated soil samples from the industrial park in Taolin Town, Lianyungang, China. The whole genome of the strain was sequenced and analyzed to reveal its genomic potential. The oil degradation and growth conditions including nitrogen, and phosphorus sources, degradation cycle, biological dosing, pH, and oil concentration were optimized to exploit its commercial application. The genome of the DH7 strain contains 4,705,032 bp with GC content of 54.95% and 4653 genes. The genome analysis revealed that there are several metabolic pathways and enzyme-encoding genes related to oil degradation in the DH7 genome, such as the paa gene cluster which is involved in the phenylacetic acid degradation pathway, and complete degradation pathways for fatty acid and benzoate, genes related to chlorinated alkanes and olefins degradation pathway including adhP, frmA, and adhE, etc. The strain DH7 under the optimized conditions has demonstrated a maximum degradation efficiency of 84.6% after 14 days of treatment using synthetic oil, which comparatively displays a higher oil degradation efficiency than any Enterobacter species known to date. To the best of our knowledge, this study presents the first-ever genomic studies related to the oil degradation potential of any Enterobacter species. As Enterobacter kobei DH7 has demonstrated significant oil degradation potential, it is one of the good candidates for application in the bioremediation of oil-contaminated environments.

Utilization of glycosyltransferases as a seamless tool for synthesis and modification of the oligosaccharides-A review.

Glycosyltransferases (GTs) catalyze the transfer of active monosaccharide donors to carbohydrates to create a wide range of oligosaccharide structures. GTs display strong regioselectivity and stereoselectivity in producing glycosidic bonds, making them extremely valuable in the in vitro synthesis of oligosaccharides. The synthesis of oligosaccharides by GTs often gives high yields; however, the enzyme activity may experience product inhibition. Additionally, the higher cost of nucleotide sugars limits the usage of GTs for oligosaccharide synthesis. In this review, we comprehensively discussed the structure and mechanism of GTs based on recent literature and the CAZY website data. To provide innovative ideas for the functional studies of GTs, we summarized several remarkable characteristics of GTs, including folding, substrate specificity, regioselectivity, donor sugar nucleotides, catalytic reversibility, and differences between GTs and GHs. In particular, we highlighted the recent advancements in multi-enzyme cascade reactions and co-immobilization of GTs, focusing on overcoming problems with product inhibition and cost issues. Finally, we presented various types of GT that have been successfully used for oligosaccharide synthesis. We concluded that there is still an opportunity for improvement in enzymatically produced oligosaccharide yield, and future research should focus on improving the yield and reducing the production cost.

Optimization of heterologous production of Bacillus ligniniphilus L1 laccase in Escherichia coli through statistical design of experiments.

Laccases are powerful multi-copper oxidoreductases that have wide applicability as "green" biocatalysts in biotechnological, bioremediation, and industrial applications. Sustainable production of large amounts of functional laccases from original sources is limited by low yields, difficulties in purification, slow growth of the organisms, and high cost of production. Harnessing the full potential of these versatile biocatalysts will require the development of efficient heterologous systems that allow high-yield, scalable, and cost-effective production. We previously cloned a temperature- and pH-stable laccase from Bacillus ligniniphilus L1 (L1-lacc) that demonstrated remarkable activity in the oxidation of lignin and delignification for bioethanol production. However, L1-lacc is limited by low enzyme yields in both the source organism and heterologous systems. Here, to improve production yields and lower the cost of production, we optimized the recombinant E. coli BL21 strain for high-level production of L1-lacc. Several culture medium components and fermentation parameters were optimized using one-factor-at-a-time (OFAT) and Plackett-Burman design (PBD) to screen for important factors that were then optimized using response surface methodology (RSM) and an orthogonal design. The optimized medium composition had compound nitrogen (15.6 g/L), glucose (21.5 g/L), K2HPO4 (0.15 g/L), MgSO4 (1 g/L), and NaCl (7.5 g/L), which allowed a 3.3-fold yield improvement while subsequent optimization of eight fermentation parameters achieved further improvements to a final volumetric activity titer of 5.94 U/mL in 24 h. This represents a 7-fold yield increase compared to the initial medium and fermentation conditions. This work presents statistically guided optimization strategies for improving heterologous production of a bacterial laccase that resulted in a high-yielding, cost-efficient production system for an enzyme with promising applications in lignin valorization, biomass processing, and generation of novel composite thermoplastics.

Astaxanthin production from the microalga Haematococcus lacustris with a dual substrate mixotrophy strategy.

This study investigates the development of dual-substrate mixotrophy strategy to cultivate the microalga Haematococcus lacustris for astaxanthin production. The influence of different concentrations of acetate and pyruvate on biomass productivity was first assessed individually, and then both substrates were used together to improve biomass growth in the green phase and astaxanthin accumulation in red the phase. The results showed that dual-substrates mixotrophy significantly increased the biomass productivity during green growth phase up to 2-fold compared to phototrophic controls. Furthermore, supplementation of dual-substrate to the red phase increased astaxanthin accumulation by 10% in the dual-substrate group compared to single-substrate acetate and no substrate. This dual-substrate mixotrophy approach shows promise for cultivating Haematococcus for commercial production of biological astaxanthin in indoor closed systems.

Bioplastic production in terms of life cycle assessment: A state-of-the-art review.

The current transition to sustainability and the circular economy can be viewed as a socio-technical response to environmental impacts and the need to enhance the overall performance of the linear production and consumption paradigm. The concept of biowaste refineries as a feasible alternative to petroleum refineries has gained popularity. Biowaste has become an important raw material source for developing bioproducts and biofuels. Therefore, effective environmental biowaste management systems for the production of bioproducts and biofuels are crucial and can be employed as pillars of a circular economy. Bioplastics, typically plastics manufactured from bio-based polymers, stand to contribute to more sustainable commercial plastic life cycles as part of a circular economy in which virgin polymers are made from renewable or recycled raw materials. Various frameworks and strategies are utilized to model and illustrate additional patterns in fossil fuel and bioplastic feedstock prices for various governments' long-term policies. This review paper highlights the harmful impacts of fossil-based plastic on the environment and human health, as well as the mass need for eco-friendly alternatives such as biodegradable bioplastics. Utilizing new types of bioplastics derived from renewable resources (e.g., biowastes, agricultural wastes, or microalgae) and choosing the appropriate end-of-life option (e.g., anaerobic digestion) may be the right direction to ensure the sustainability of bioplastic production. Clear regulation and financial incentives are still required to scale from niche polymers to large-scale bioplastic market applications with a truly sustainable impact.

Host-Specific Diversity of Culturable Bacteria in the Gut Systems of Fungus-Growing Termites and Their Potential Functions towards Lignocellulose Bioconversion.

Fungus-growing termites are eusocial insects that represent one of the most efficient and unique systems for lignocellulose bioconversion, evolved from a sophisticated symbiosis with lignocellulolytic fungi and gut bacterial communities. Despite a plethora of information generated during the last century, some essential information on gut bacterial profiles and their unique contributions to wood digestion in some fungus-growing termites is still inadequate. Hence, using the culture-dependent approach, the present study aims to assess and compare the diversity of lignocellulose-degrading bacterial symbionts within the gut systems of three fungus-growing termites: Ancistrotermes pakistanicus, Odontotermes longignathus, and Macrotermes sp. A total of 32 bacterial species, belonging to 18 genera and 10 different families, were successfully isolated and identified from three fungus-growing termites using Avicel or xylan as the sole source of carbon. Enterobacteriaceae was the most dominant family represented by 68.1% of the total bacteria, followed by Yersiniaceae (10.6%) and Moraxellaceae (9%). Interestingly, five bacterial genera such as Enterobacter, Citrobacter, Acinetobacter, Trabulsiella, and Kluyvera were common among the tested termites, while the other bacteria demonstrated a termite-specific distribution. Further, the lignocellulolytic potential of selected bacterial strains was tested on agricultural waste to evaluate their capability for lignocellulose bioconversion. The highest substrate degradation was achieved with E. chengduensis MA11 which degraded 45.52% of rice straw. All of the potential strains showed endoglucanase, exoglucanase, and xylanase activities depicting a symbiotic role towards the lignocellulose digestion within the termite gut. The above results indicated that fungus-growing termites harbor a diverse array of bacterial symbionts that differ from species to species, which may play an inevitable role to enhance the degradation efficacy in lignocellulose decomposition. The present study further elaborates our knowledge about the termite-bacteria symbiosis for lignocellulose bioconversion which could be helpful to design a future biorefinery.