Biochemical Production Research Articles

Engineering and finetuning expression of SerC for balanced metabolic flux in vitamin B6 production

Vitamin B6 plays a crucial role in cellular metabolism and stress response, making it an essential component for growth in all known organisms. However, achieving efficient biosynthesis of vitamin B6 faces the challenge of maintaining a balanced distribution of metabolic flux between growth and production. In this study, our focus is on addressing this challenge through the engineering of phosphoserine aminotransferase (SerC) to resolve its redundancy and promiscuity. The enzyme SerC was semi-designed and screened based on sequences and predicted kcat values, respectively. Mutants and heterologous proteins showing potential were then fine-tuned to optimize the production of vitamin B6. The resulting strain enhances the production of vitamin B6, indicating that different fluxes are distributed to the biosynthesis pathway of serine and vitamin B6. This study presents a promising strategy to address the challenge posed by multifunctional enzymes, with significant implications for enhancing biochemical production through engineering processes.

Revealing the occurrence of refractory melanoidins and inhibitions on anaerobic fermentation via thermal hydrolysis pretreatment

Thermal hydrolysis pretreatment (THP) is widely used to promote the hydrolysis of polysaccharides and proteins in waste activated sludge (WAS). However, it also generates unwanted refractory organics of melanoidins products (MPs), which should not be overlooked, especially concerning the occurrence and inhibition of hydrolases and anaerobes. In this study, the MPs occurrence by THP was investigated and inhibition mechanism on anaerobic fermentation was revealed for the first time. The results showed that SCOD in WAS significantly increased from 0.5±0.02 g/L in control to 4.1±0.02 g/L in THP at 180 °C. However, the color of MPs under a higher temperature (>120 °C) changed from colourless to dark brown. The components of MPs were mainly nitrogenous and humic acid-like refractory organics. Unwanted MPs generated above 160 °C reduced methane production by 49.1 %–89.8 %, which was due to the inhibition of protease, acidogenic bacteria, and acetoclastic methanogens. Inhibition of acetoclastic methanogens also resulted in the accumulation of VFAs. The microbial diversity clearly showed that the toxicity of MPs altered the microbial community structure, reducing the proportion of both acidogenic bacteria and acetoclastic methanogens. Therefore, the negative effect of MPs on anaerobic digestion demonstrated that THP should be re-evaluated in the production of biochemicals, which is important for achieving carbon neutrality of WWTPs in the future.

Hybrid AI modeling techniques for pilot scale bubble column aeration: A comparative study

With increased accessibility of process data from the production lines in chemical and biochemical production plants, the use of data-based modeling methods is gaining interest. In this work, three different data-based modeling approaches are applied for modeling aeration in a pilot scale bubble column. In all three modeling approaches the same serial hybrid-model structure is used, combining a species conservation balance based on first-principles with different data-based models for the overall volumetric mass transfer coefficient (KLa). Simple empirical correlations with parameters fit to process data provide transparent models but lack the accuracy of Artificial Neural Networks (ANNs). ANNs provide models with high accuracy within the operation regimes used for training, however, the models are prone to overfitting, and their black-box nature results in models that are difficult to interpret. As an alternative, a symbolic regression-inspired technique is used for discovering symbolic equations, resulting in interpretable models with accuracy that is comparable to that of the ANN.

Enhancing enzymatic saccharification yields of cellulose at high solid loadings by combining different LPMO activities

BackgroundThe polysaccharides in lignocellulosic biomass hold potential for production of biofuels and biochemicals. However, achieving efficient conversion of this resource into fermentable sugars faces challenges, especially when operating at industrially relevant high solid loadings. While it is clear that combining classical hydrolytic enzymes and lytic polysaccharide monooxygenases (LPMOs) is necessary to achieve high saccharification yields, exactly how these enzymes synergize at high solid loadings remains unclear.ResultsAn LPMO-poor cellulase cocktail, Celluclast 1.5 L, was spiked with one or both of two fungal LPMOs from Thermothielavioides terrestris and Thermoascus aurantiacus, TtAA9E and TaAA9A, respectively, to assess their impact on cellulose saccharification efficiency at high dry matter loading, using Avicel and steam-exploded wheat straw as substrates. The results demonstrate that LPMOs can mitigate the reduction in saccharification efficiency associated with high dry matter contents. The positive effect of LPMO inclusion depends on the type of feedstock and the type of LPMO and increases with the increasing dry matter content and reaction time. Furthermore, our results show that chelating free copper, which may leak out of the active site of inactivated LPMOs during saccharification, with EDTA prevents side reactions with in situ generated H2O2 and the reductant (ascorbic acid).ConclusionsThis study shows that sustaining LPMO activity is vital for efficient cellulose solubilization at high substrate loadings. LPMO cleavage of cellulose at high dry matter loadings results in new chain ends and thus increased water accessibility leading to decrystallization of the substrate, all factors making the substrate more accessible to cellulase action. Additionally, this work highlights the importance of preventing LPMO inactivation and its potential detrimental impact on all enzymes in the reaction.

Kinetics-based development of two-stage continuous fermentation of 1,3-propanediol from crude glycerol by Clostridium butyricum

BackgroundGlycerol, as a by-product, mainly derives from the conversion of many crops to biodiesel, ethanol, and fatty ester. Its bioconversion to 1,3-propanediol (1,3-PDO) is an environmentally friendly method. Continuous fermentation has many striking merits over fed-batch and batch fermentation, such as high product concentration with easy feeding operation, long-term high productivity without frequent seed culture, and energy-intensive sterilization. However, it is usually difficult to harvest high product concentrations.ResultsIn this study, a three-stage continuous fermentation was firstly designed to produce 1,3-PDO from crude glycerol by Clostridium butyricum, in which the first stage fermentation was responsible for providing the excellent cells in a robust growth state, the second stage focused on promoting 1,3-PDO production, and the third stage aimed to further boost the 1,3-PDO concentration and reduce the residual glycerol concentration as much as possible. Through the three-stage continuous fermentation, 80.05 g/L 1,3-PDO as the maximum concentration was produced while maintaining residual glycerol of 5.87 g/L, achieving a yield of 0.48 g/g and a productivity of 3.67 g/(L·h). Based on the 14 sets of experimental data from the first stage, a kinetic model was developed to describe the intricate relationships among the concentrations of 1,3-PDO, substrate, biomass, and butyrate. Subsequently, this kinetic model was used to optimize and predict the highest 1,3-PDO productivity of 11.26 g/(L·h) in the first stage fermentation, while the glycerol feeding concentration and dilution rate were determined to be 92 g/L and 0.341 h−1, separately. Additionally, to achieve a target 1,3-PDO production of 80 g/L without the third stage fermentation, the predicted minimum volume ratio of the second fermenter to the first one was 11.9. The kinetics-based two-stage continuous fermentation was experimentally verified well with the predicted results.ConclusionA novel three-stage continuous fermentation and a kinetic model were reported. Then a simpler two-stage continuous fermentation was developed based on the optimization of the kinetic model. This kinetics-based development of two-stage continuous fermentation could achieve high-level production of 1,3-PDO. Meanwhile, it provides a reference for other bio-chemicals production by applying kinetics to optimize multi-stage continuous fermentation.Graphical

Sesquiterpenes of the ectomycorrhizal fungus Pisolithus microcarpus alter root growth and promote host colonization

Trees form symbioses with ectomycorrhizal (ECM) fungi, maintained in part through mutual benefit to both organisms. Our understanding of the signaling events leading to the successful interaction between the two partners requires further study. This is especially true for understanding the role of volatile signals produced by ECM fungi. Terpenoids are a predominant class of volatiles produced by ECM fungi. While several ECM genomes are enriched in the enzymes responsible for the production of these volatiles (i.e., terpene synthases (TPSs)) when compared to other fungi, we have limited understanding of the biochemical products associated with each enzyme and the physiological impact of specific terpenes on plant growth. Using a combination of phylogenetic analyses, RNA sequencing, and functional characterization of five TPSs from two distantly related ECM fungi (Laccaria bicolor and Pisolithus microcarpus), we investigated the role of these secondary metabolites during the establishment of symbiosis. We found that despite phylogenetic divergence, these TPSs produced very similar terpene profiles. We focused on the role of P. microcarpus terpenes and found that the fungus expressed a diverse array of mono-, di-, and sesquiterpenes prior to contact with the host. However, these metabolites were repressed following physical contact with the host Eucalyptus grandis. Exposure of E. grandis to heterologously produced terpenes (enriched primarily in γ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\gamma$$\\end{document}-cadinene) led to a reduction in the root growth rate and an increase in P. microcarpus–colonized root tips. These results support a very early putative role of fungal-produced terpenes in the establishment of symbiosis between mycorrhizal fungi and their hosts.

Toxicity and Risk of Biopesticides to Insect Pollinators in Urban and Agricultural Landscapes

Pollinators play important roles in providing pollination services, maintaining biodiversity, and boosting crop production. Even though pollinators are essential to the environment and agriculture, their decline has been noted across multiple studies in the recent past. Both natural and anthropogenic factors have contributed to their decline. Much of the focus has been placed on climate change, habitat loss, pests and pathogens, and synthetic pesticides, but relatively little is known about the effects of biopesticides. Biopesticides are biological control agents derived from living organisms and are classified into three groups: microbial, biochemical, and plant-incorporated protectant-based products. Biopesticides are formulated similarly to their synthetic counterparts and are readily available and used within urban and agricultural settings by pest management experts and household residents. The general public and much scientific literature support the prevailing idea that biopesticides are environmentally safe and pollinator friendly in comparison with synthetic versions. However, such generalizations are based on studies with a few key pollinator species and may not be relevant to several other species that provide crop pollination services. Studies focused on native pollinators have shown that some biopesticides have lethal and sublethal effects. Because each biopesticide exhibits varying effects across pollinator species, it could be dangerous to generalize their non-toxicity across taxa and environmental settings. In this article, recent research in this direction is discussed.

Solid-state fermentation of brown seaweeds for the production of alginate lyase using marine bacterium Enterobacter tabaci RAU2C.

Alginate lyases have countless potential for application in industries and medicine particularly as an appealing biocatalyst for the production of biofuels and bioactive oligosaccharides. Solid-state fermentation (SSF) allows improved production of enzymes and consumes less energy compared to submerged fermentation. Seaweeds can serve as the most promising biomass for the production of biochemicals. Alginate present in the seaweed can be used by alginate lyase-producing bacteria to support growth and can secrete alginate lyase. In this perspective, the current study was directed on the bioprocessing of brown seaweeds for the production of alginate lyase using marine bacterial isolate. A novel alginate-degrading marine bacterium Enterobacter tabaci RAU2C which was previously isolated in the laboratory was used for the production of alginate lyase using Sargassum swartzii as a low-cost solid substrate. Process parameters such as inoculum incubation period and moisture content were optimized for alginate lyase production. SSF resulted in 33.56 U/mL of alginate lyase under the static condition maintained with 75% moisture after 4days. Further, the effect of different buffers, pH, and temperature on alginate lyase activity was also analyzed. An increase in alginate lyase activity was observed with an increase in moisture content from 60 to 75%. Maximum enzyme activity was perceived with phosphate buffer at pH 7 and 37°C. Further, the residual biomass after SSF could be employed as biofertilizer for plant growth promotion based on the preliminary analysis. To our knowledge, this is the first report stating the usage of seaweed biomass as a substrate for the production of alginate lyase using solid-state fermentation.

Quantum dot-based light conversion strategy for customized cultivation of microalgae

Microalgae are photosynthetic microorganisms with the potential to mitigate the atmospheric greenhouse effect by carbon fixation. However, their growth is typically limited by light availability. A wavelength converter utilizing red, blue, and green quantum dots (QDs) was developed to optimize light quality for enhancing microalgal production. The growth, lipid content, and eicosapentaenoic acid titer of Nannochloropsis increased by 11.2%, 9.5%, and 15.5% with red QDs, respectively. The biomass and triacylglycerol content of Phaeodactylum tricornutum increased by 8.6% and 35.0%, respectively. Simultaneously, biodiesel production was accelerated in Nannochloropsis (20.2%) and P. tricornutum (11.6%), and improved with increased cetane number and reduced iodine value. Furthermore, red QDs increased the growth and biomass accumulation of Nannochloropsis under low light, while green QDs shielded Nannochloropsis from photoinhibition under high light. This customizable QD-based methodology overcomes microalgal light limitations, demonstrating a universally applicable approach to improve microalgal cultivation and biochemical component production.

The Immune Landscape of Pheochromocytoma and Paraganglioma: Current Advances and Perspectives.

Pheochromocytomas and paragangliomas (PPGLs) are rare neuroendocrine tumors derived from neural crest cells from adrenal medullary chromaffin tissues and extra-adrenal paraganglia, respectively. Although the current treatment for PPGLs is surgery, optimal treatment options for advanced and metastatic cases have been limited. Hence, understanding the role of the immune system in PPGL tumorigenesis can provide essential knowledge for the development of better therapeutic and tumor management strategies, especially for those with advanced and metastatic PPGLs. The first part of this review outlines the fundamental principles of the immune system and tumor microenvironment, and their role in cancer immunoediting, particularly emphasizing PPGLs. We focus on how the unique pathophysiology of PPGLs, such as their high molecular, biochemical, and imaging heterogeneity and production of several oncometabolites, creates a tumor-specific microenvironment and immunologically "cold" tumors. Thereafter, we discuss recently published studies related to the reclustering of PPGLs based on their immune signature. The second part of this review discusses future perspectives in PPGL management, including immunodiagnostic and promising immunotherapeutic approaches for converting "cold" tumors into immunologically active or "hot" tumors known for their better immunotherapy response and patient outcomes. Special emphasis is placed on potent immune-related imaging strategies and immune signatures that could be used for the reclassification, prognostication, and management of these tumors to improve patient care and prognosis. Furthermore, we introduce currently available immunotherapies and their possible combinations with other available therapies as an emerging treatment for PPGLs that targets hostile tumor environments.

The application of process simulations in lignocellulosic biorefinery: a review

AbstractIn recent years there has been a growing interest in the scale‐up and commercialization of lignocellulosic biorefinery. Process simulation is a crucial preliminary study, conducted at the system level, to evaluate the feasibility of industrializing biorefinery operations. Numerous research studies have been conducted on the application of process simulation in lignocellulosic biorefinery, making it essential to provide a detailed introduction to this topic. This paper summarizes two aspects of the application of process simulation in lignocellulosic biorefinery: the production of bioenergy and the production of biochemicals. The bioenergy section describes the application of process simulation to hydrochar, syngas, and bioethanol. The biochemicals section relates to the production processes for cellulose, lignin, and hemicellulose. Additionally, the research status of process simulation in biorefinery are detailed from the following aspects: physical property parameters, kinetic study, the variety of raw materials and validation. Finally, this paper discusses some advances in biorefinery process simulation. It is hoped that this paper will assist the industrialization of lignocellulosic biorefinery.

Biosynthesis of NPs CuS/Cu2S and self-assembly with C. beijerinckii for improving lignocellulosic butanol production in staged butyrate-butanol fermentation process

A staged butyrate-butanol fermentation process (SBBFP) has been developed to efficiently produce biobutanol from renewable lignocellulose. The SBBFP combines the fermentation of bioaugmented degradation consortium for butyrate (BDCB) and butanol production of Clostridium beijerinckii, but is still challenged by the lower specific butanol yield (SBY). In this study, a novel technology for synthesizing semiconductor nanoparticles (NPs) and their self-assembly with Clostridium beijerinckii was proposed to enhance the SBY. Results showed that supplement of 0.1 g/L CuSO4 or 0.2 g/L ZnSO4 were more favorable for the formation of butyrate and NPs (CuS/Cu2S or ZnS) in the acidogenic fermentation process of BDCB. Butyrate production achieved 19–21 g/L in the fed-batch fermentation mode from NaOH-pretreated rice straw. Only CuS/Cu2S can be assembled with NPs@C. beijerinckii hybrid system, and a butanol production of 14.6 g/L was obtained using acidogenic fermentation broth and saccharide liquid from rice straw as the co-substrates, with the SBY of 0.17 g/g initial pretreated rice straw. The enhanced butanol synthesis was likely attributed to the upgraded intracellular NADH/NAD+ and specific activity of enzyme CoA-transferase (ctfAB) in C. beijerinckii. The research work provides an efficient approach for biofuels and biochemical production from lignocellulose, along with the extended application of biological nanotechnology.

Enzymatic hydrolysis of cellulose banana stem (alkaline microwave-assisted pre-treatment)

The banana stem waste holds immense promise as a readily available and abundant source of lignocellulosic biomass, making it a compelling alternative for biofuel and biochemical applications. Therefore, this study focuses on investigating the impact of both time and substrate loading on the enzymatic hydrolysis of banana stem cellulose that has undergone alkaline microwave-assisted pre-treatment. The pre-treatment method involves subjecting the biomass to 5% KOH for 30 min, followed by microwave exposure at 300 W for 5 min, a process aimed at enhancing the accessibility of cellulose. Enzymatic hydrolysis experiments were carried out utilizing cellulase enzymes derived from Aspergillus niger, with variations in hydrolysis times (ranging from 5 to 45 h) and enzyme-to-substrate ratios (ranging from 1:1 to 1:10). The results of this investigation revealed a substantial improvement in hydrolysis efficiency, owing to the synergistic effects of alkaline microwave-assisted pre-treatment, signifying enhanced cellulose accessibility. Notably, the highest concentration of reducing sugars (1.3 mg mL−1) was achieved at a substrate-to-enzyme ratio of 1:1 and a hydrolysis duration of 45 h. These findings provide valuable insights into the conversion of lignocellulosic biomass, emphasizing the potential of integrated pre-treatment strategies for sustainable biorefinery applications. This research contributes to advancing our understanding of lignocellulosic biomass utilization, offering a promising avenue for biofuel and biochemical production from banana stem waste.

Sustainable Production of Biofuels and Biochemicals via Electro-Fermentation Technology.

The energy crisis and climate change are two of the most concerning issues for human beings nowadays. For that reason, the scientific community is focused on the search for alternative biofuels to conventional fossil fuels as well as the development of sustainable processes to develop a circular economy. Bioelectrochemical processes have been demonstrated to be useful for producing bioenergy and value-added products from several types of waste. Electro-fermentation has gained great attention in the last few years due to its potential contribution to biofuel and biochemical production, e.g., hydrogen, methane, biopolymers, etc. Conventional fermentation processes pose several limitations in terms of their practical and economic feasibility. The introduction of two electrodes in a bioreactor allows the regulation of redox instabilities that occur in conventional fermentation, boosting the overall process towards a high biomass yield and enhanced product formation. In this regard, key parameters such as the type of culture, the nature of the electrodes as well as the operating conditions are crucial in order to maximize the production of biofuels and biochemicals via electro-fermentation technology. This article comprises a critical overview of the benefits and limitations of this emerging bio-electrochemical technology and its contribution to the circular economy.

Optimizing Enzymatic Hydrolysis Pathways: A Comprehensive Study on Enhancing Cellulose Bioconversion Efficiency for Industrial Applications

Abstract: This research paper presents a comprehensive investigation into optimizing enzymatic hydrolysis pathways for cellulose bioconversion, with a focus on enhancing efficiency for industrial applications. Cellulose, a major component of plant biomass, is a sustainable feedstock with immense potential for biofuel and biochemical production. However, its recalcitrant nature poses challenges in terms of effective conversion. The study addresses this challenge by delving into the intricate details of enzymatic hydrolysis, aiming to unlock the full potential of cellulose-derived products. The research employs advanced enzymatic technologies, exploring novel enzymes and enzyme cocktails to enhance cellulose breakdown. By systematically analyzing the enzymatic hydrolysis pathways, the study seeks to identify key factors influencing efficiency and propose targeted optimization strategies. Experimental validations and data-driven insights contribute to a nuanced understanding of cellulose bioconversion mechanisms. Furthermore, the paper emphasizes the industrial applicability of the proposed strategies. It discusses scalability, cost-effectiveness, and feasibility, ensuring that the optimized enzymatic hydrolysis pathways align with the practical demands of large-scale production. The integration of cutting-edge bioprocessing technologies and innovative enzymatic approaches underscores the potential for significant advancements in cellulose bioconversion for industrial settings. This research not only contributes valuable insights to the scientific community but also addresses the pressing need for sustainable and efficient bioconversion strategies, laying the foundation for a more environmentally friendly and economically viable bio-based industry.

Molecular Study on Conformational Changes in Trypsin Inhibitors in Multidirectional Electrostatic Fields

Proteins undergo a series of conformational changes when affected by the applied electric field, which changes their functions and properties. The conformational changes in proteins in various electric fields are different due to their internal structures. This study simulates the molecular dynamics of proteins in different amounts and directions of electric fields with gromacs software. According to the root mean square deviation, hydrogen bond, dipole moment, and solvent accessible surface area, it is proved that the conformation change in proteins is more drastic under the simultaneous action of multiple electric fields under various directions, and different fragments unfold with divergent electric fields combined, which is of great importance to control protein function, improve biochemical research and production efficiency in the food and drug safety field.

Simultaneous glucose and xylose utilization by an Escherichia coli catabolite repression mutant.

As advances are made toward the industrial feasibility of mass-producing biofuels and commodity chemicals with sugar-fermenting microbes, high feedstock costs continue to inhibit commercial application. Hydrolyzed lignocellulosic biomass represents an ideal feedstock for these purposes as it is cheap and prevalent. However, many microbes, including Escherichia coli, struggle to efficiently utilize this mixture of hexose and pentose sugars due to the regulation of the carbon catabolite repression (CCR) system. CCR causes a sequential utilization of sugars, rather than simultaneous utilization, resulting in reduced carbon yield and complex process implications in fed-batch fermentation. A mutant of the gene encoding the cyclic AMP receptor protein, crp*, has been shown to disable CCR and improve the co-utilization of mixed sugar substrates. Here, we present the strain construction and characterization of a site-specific crp* chromosomal mutant in E. coli BL21 star (DE3). The crp* mutant strain demonstrates simultaneous consumption of glucose and xylose, suggesting a deregulated CCR system. The proteomics further showed that glucose was routed to the C5 carbon utilization pathways to support both de novo nucleotide synthesis and energy production in the crp* mutant strain. Metabolite analyses further show that overflow metabolism contributes to the slower growth in the crp* mutant. This highly characterized strain can be particularly beneficial for chemical production by simultaneously utilizing both C5 and C6 substrates from lignocellulosic biomass.IMPORTANCEAs the need for renewable biofuel and biochemical production processes continues to grow, there is an associated need for microbial technology capable of utilizing cheap, widely available, and renewable carbon substrates. This work details the construction and characterization of the first B-lineage Escherichia coli strain with mutated cyclic AMP receptor protein, Crp*, which deregulates the carbon catabolite repression (CCR) system and enables the co-utilization of multiple sugar sources in the growth medium. In this study, we focus our analysis on glucose and xylose utilization as these two sugars are the primary components in lignocellulosic biomass hydrolysate, a promising renewable carbon feedstock for industrial bioprocesses. This strain is valuable to the field as it enables the use of mixed sugar sources in traditional fed-batch based approaches, whereas the wild-type carbon catabolite repression system leads to biphasic growth and possible buildup of non-preferential sugars, reducing process efficiency at scale.

Distribution, Diversity and Biochemical Analysis of Endophytic Fungi Associated with Chromolaena odorata

Chromolaena odorata is a medicinal plant that possesses several properties, including antibacterial, antifungal, anti-inflammatory, anticancer, antioxidant, etc., and has been used in traditional medicine in various parts of the world. Medicinal plants are associated with endophytic fungi that have potential biological activities as well as protect the plant from biotic and abiotic agents. In this study, endophytic fungi were isolated from the leaves, stems, roots, and inflorescence of C. odorata and identified morphologically. Nineteen sporulating endophytic fungi belonging to 9 genera, 8 families and 4 classes, and three sterile forms were obtained. The isolation data recorded were used to calculate Isolation rate, Colonization frequency, Infection rate and Relative occurrence of different groups of fungi. The highest Isolation rate was found in the stem part (34.75%); the highest overall Colonization frequency (%) was shown by Chaetomium globosum (8.51%); the maximum Infection rate was found in root segments (77.86%); and the maximum isolate belongs to Sordariomycetes, showing 43.50%. Simpson’s dominance index, Simpson’s diversity index, Species richness, Shannon-Wiener index and Evenness (E) index were calculated to reveal diversity indices. The maximum diversity was recorded in the leaf part (0.99), and the maximum number of endophytic fungal species was observed in stem segments. The production of biochemicals was analyzed qualitatively, and it was observed that all the isolates produce flavonoids and phenols. This indicates that endophytic fungi are a storehouse of natural compounds and can be applied in agriculture, medicine, and pharmaceutical industries.

Positive effect of phasin in biohydrogen production of non polyhydroxybutyrate-producing Clostridium acetobutylicum ATCC 824

In this study, the goal was to enhance the tolerance of Clostridium acetobutylicum ATCC 824 to biomass-based inhibitory compounds for biohydrogen production and evaluate various known genes that enhance the production of biochemicals in various hosts. The introduction of phaP, the major polyhydroxyalkanoate granule-associated protein that has been reported as a chaperone-like protein resulted in increased tolerance to inhibitors and leads to higher levels of hydrogen production, cell growth, and glucose consumption in the presence of these inhibitors. It was observed that the introduction of phaP led to an increase in the transcription of the hydrogenase gene, whereas transcription of the chaperone functional genes decreased compared to the wild type. Finally, the introduction of phaP could significantly enhance biohydrogen production by 2.6-fold from lignocellulosic hydrolysates compared to that of wild type. These findings suggested that the introduction of phaP could enhance growth and biohydrogen production, even in non-polyhydroxyalkanoate-producing strains.

Interdisciplinary Research on Electrons and Biofilms

Interdisciplinary research on electrons and biofilms is being carried out by Assistant Professor Dr Yoshihide Tokunou, Faculty of Life and Environmental Sciences, University of Tsukuba, Japan. His work is aimed at gaining a deeper understanding of the role of electrons in bacterial society and exploring the process of bacterial extracellular electron transfer (EET) in biofilms. By combining microbiology and electrochemistry, Dr Tokunou is developing EET-based biotechnologies and improving our understanding of the physiological importance of EET in bacterial society. To achieve this, he is collaborating with various experts such as microbiologists, chemists, and engineers, including Professor Dr Nobuhiko Nomura. His current interest is in the EET process that terminates with soluble electron acceptors. By regulating the EET in biofilms respiring with oxygen, he is trying to control various biofilm-related phenomena such as host-bacteria interaction, antibiotic resistance of biofilms, biochemical production from biofilms, etc.