Biotechnology for Biofuels最新文献

{"title":"The overexpression of the switchgrass (Panicum virgatum L.) genes PvTOC1-N or PvLHY-K affects circadian rhythm and hormone metabolism in transgenic Arabidopsis seedlings","authors":"Shumeng Zhang,&nbsp;Jiayang Ma,&nbsp;Weiwei Wang,&nbsp;Chao Zhang,&nbsp;Fengli Sun,&nbsp;Yajun Xi","doi":"10.1186/s13068-024-02574-6","DOIUrl":"10.1186/s13068-024-02574-6","url":null,"abstract":"<div><p>Switchgrass (<i>Panicum virgatum</i> L.) is a perennial C4 warm-season grass known for its high-biomass yield and wide environmental adaptability, making it an ideal bioenergy crop. Despite its potential, switchgrass seedlings grow slowly, often losing out to weeds in field conditions and producing limited biomass in the first year of planting. Furthermore, during the reproductive growth stage, the above-ground biomass rapidly increases in lignin content, creating a significant saccharification barrier. Previous studies have identified rhythm-related genes <i>TOC1</i> and <i>LHY</i> as crucial to the slow seedling development in switchgrass, yet the precise regulatory functions of these genes remain largely unexplored. In this study, the genes <i>TOC1</i> and <i>LHY</i> were characterized within the tetraploid genome of switchgrass. Gene expression analysis revealed that <i>PvTOC1</i> and <i>PvLHY</i> exhibit circadian patterns under normal growth conditions, with opposing expression levels over time. <i>PvTOC1</i> genes were predominantly expressed in florets, vascular bundles, and seeds, while <i>PvLHY</i> genes showed higher expression in stems, leaf sheaths, and nodes. Overexpression of <i>PvTOC1</i> from the N chromosome group (<i>PvTOC1-N</i>) or <i>PvLHY</i> from the K chromosome group (<i>PvLHY-K</i>) in <i>Arabidopsis thaliana</i> led to alterations in circadian rhythm and hormone metabolism, resulting in shorter roots, delayed flowering, and decreased resistance to oxidative stress. These transgenic lines exhibited reduced sensitivity to hormones and hormone inhibitors, and displayed altered gene expression in the biosynthesis and signal transduction pathways of abscisic acid (ABA), gibberellin (GA), 3-indoleacetic acid (IAA), and strigolactone (SL). These findings highlight roles of <i>PvTOC1-N</i> and <i>PvLHY-K</i> in plant development and offer a theoretical foundation for genetic improvements in switchgrass and other crops.</p></div>","PeriodicalId":494,"journal":{"name":"Biotechnology for Biofuels","volume":"17 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://biotechnologyforbiofuels.biomedcentral.com/counter/pdf/10.1186/s13068-024-02574-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142373793","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Efficient enhancement of the antimicrobial activity of Chlamydomonas reinhardtii extract by transgene expression and molecular modification using ionizing radiation","authors":"Shubham Kumar Dubey,&nbsp;Seung Sik Lee,&nbsp;Jin-Hong Kim","doi":"10.1186/s13068-024-02575-5","DOIUrl":"10.1186/s13068-024-02575-5","url":null,"abstract":"<div><h3>Background</h3><p>Ionizing radiation has been used for mutagenesis or material modification. The potential to use microalgae as a platform for antimicrobial production has been reported, but little work has been done to advance it beyond characterization to biotechnology. This study explored two different applications of ionizing radiation as a metabolic remodeler and a molecular modifier to enhance the antimicrobial activity of total protein and solvent extracts of <i>Chlamydomonas reinhardtii</i> cells.</p><h3>Results</h3><p>First, highly efficient transgenic <i>C. reinhardtii</i> strains expressing the plant-derived antimicrobial peptides, AtPR1 or AtTHI2.1, were developed using the radiation-inducible promoter, <i>CrRPA70Ap</i>. Low transgene expression was significantly improved through X-irradiation (12–50 Gy), with peak activity observed within 2 h. Protein extracts from these strains after X-irradiation showed enhanced antimicrobial activity against the prokaryotic bacterium, <i>Pseudomonas syringae</i>, and the eukaryotic fungus, <i>Cryptococcus neoformans</i>. In addition, X-irradiation (12 Gy) increased the growth and biomass of the transgenic strains. Second, <i>C. reinhardtii</i> cell extracts in ethanol were γ-irradiated (5–20 kGy), leading to molecular modifications and increased antimicrobial activity against the phytopathogenic bacteria, <i>P. syringae</i> and <i>Burkholderia glumae</i>, in a dose-dependent manner. These changes were associated with alterations in fatty acid composition. When both transgenic expression of antimicrobial peptides and molecular modification of bioactive substances were applied, the antimicrobial activity of <i>C. reinhardtii</i> cell extracts was further enhanced to some extent.</p><h3>Conclusion</h3><p>Overall, these findings suggest that ionizing radiation can significantly enhance the antimicrobial potential of <i>C. reinhardtii</i> through efficient transgene expression and molecular modification of bioactive substances, making it a valuable source of natural antimicrobial agents. Ionizing radiation can act not only as a metabolic remodeler of transgene expression in microalgae but also as a molecular modifier of the bioactive substances.</p></div>","PeriodicalId":494,"journal":{"name":"Biotechnology for Biofuels","volume":"17 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://biotechnologyforbiofuels.biomedcentral.com/counter/pdf/10.1186/s13068-024-02575-5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142359789","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Process scale-up simulation and techno-economic assessment of ethanol fermentation from cheese whey","authors":"Mattia Colacicco,&nbsp;Claudia De Micco,&nbsp;Stefano Macrelli,&nbsp;Gennaro Agrimi,&nbsp;Matty Janssen,&nbsp;Maurizio Bettiga,&nbsp;Isabella Pisano","doi":"10.1186/s13068-024-02567-5","DOIUrl":"10.1186/s13068-024-02567-5","url":null,"abstract":"<div><h3>Background</h3><p>Production of cheese whey in the EU exceeded 55 million tons in 2022, resulting in lactose-rich effluents that pose significant environmental challenges. To address this issue, the present study investigated cheese-whey treatment via membrane filtration and the utilization of its components as fermentation feedstock. A simulation model was developed for an industrial-scale facility located in Italy’s Apulia region, designed to process 539 m³/day of untreated cheese-whey. The model integrated experimental data from ethanolic fermentation using a selected strain of <i>Kluyveromyces marxianus</i> in lactose-supplemented media, along with relevant published data.</p><h3>Results</h3><p>The simulation was divided into three different sections. The first section focused on cheese-whey pretreatment through membrane filtration, enabling the recovery of 56%_w/w whey protein concentrate, process water recirculation, and lactose concentration. In the second section, the recovered lactose was directed towards fermentation and downstream anhydrous ethanol production. The third section encompassed anaerobic digestion of organic residue, sludge handling, and combined heat and power production. Moreover, three different scenarios were produced based on ethanol yield on lactose (Y_E/L), biomass yield on lactose, and final lactose concentration in the medium. A techno-economic assessment based on the collected data was performed as well as a sensitivity analysis focused on economic parameters, encompassing considerations on cheese-whey by assessing its economical impact as a credit for the simulated facility, dictated by a gate fee, or as a cost by considering it a raw material. The techno-economic analysis revealed different minimum ethanol selling prices across the three scenarios. The best performance was obtained in the scenario presenting a Y_E/L = 0.45 g/g, with a minimum selling price of 1.43 €/kg. Finally, sensitivity analysis highlighted the model’s dependence on the price or credit associated with cheese-whey handling.</p><h3>Conclusions</h3><p>This work highlighted the importance of policy implementation in this kind of study, demonstrating how a gate fee approach applied to cheese-whey procurement positively impacted the final minimum selling price for ethanol across all scenarios. Additionally, considerations should be made about the implementation of the simulated process as a plug-in addition in to existing processes dealing with dairy products or handling multiple biomasses to produce ethanol.</p></div>","PeriodicalId":494,"journal":{"name":"Biotechnology for Biofuels","volume":"17 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://biotechnologyforbiofuels.biomedcentral.com/counter/pdf/10.1186/s13068-024-02567-5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142329419","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Microwave-assisted organic acids and green hydrogen production during mixed culture fermentation","authors":"Maximilian Barth,&nbsp;Magdalena Werner,&nbsp;Pascal Otto,&nbsp;Benjamin Richwien,&nbsp;Samira Bahramsari,&nbsp;Maximilian Krause,&nbsp;Benjamin Schwan,&nbsp;Christian Abendroth","doi":"10.1186/s13068-024-02573-7","DOIUrl":"10.1186/s13068-024-02573-7","url":null,"abstract":"<div><h3>Background</h3><p>The integration of anaerobic digestion into bio-based industries can create synergies that help render anaerobic digestion self-sustaining. Two-stage digesters with separate acidification stages allow for the production of green hydrogen and short-chain fatty acids, which are promising industrial products. Heat shocks can be used to foster the production of these products, the practical applicability of this treatment is often not addressed sufficiently, and the presented work therefore aims to close this gap.</p><h3>Methods</h3><p>Batch experiments were conducted in 5 L double-walled tank reactors incubated at 37 °C. Short microwave heat shocks of 25 min duration and exposure times of 5–10 min at 80 °C were performed and compared to oven heat shocks. Pairwise experimental group differences for gas production and chemical parameters were determined using ANOVA and post–hoc tests. High-throughput 16S rRNA gene amplicon sequencing was performed to analyse taxonomic profiles.</p><h3>Results</h3><p>After heat–shocking the entire seed sludge, the highest hydrogen productivity was observed at a substrate load of 50 g/l with 1.09 mol H₂/mol hexose. With 1.01 mol H₂/mol hexose, microwave-assisted treatment was not significantly different from oven-based treatments. This study emphasised the better repeatability of heat shocks with microwave-assisted experiments, revealing low variation coefficients averaging 29%. The pre-treatment with microwaves results in a high predictability and a stronger microbial community shift to <i>Clostridia</i> compared to the treatment with the oven. The pre-treatment of heat shocks supported the formation of butyric acid up to 10.8 g/l on average, with a peak of 24.01 g/l at a butyric/acetic acid ratio of 2.0.</p><h3>Conclusion</h3><p>The results support the suitability of using heat shock for the entire seed sludge rather than just a small inoculum, making the process more relevant for industrial applications. The performed microwave-based treatment has proven to be a promising alternative to oven-based treatments, which ultimately may facilitate their implementation into industrial systems. This approach becomes economically sustainable with high-temperature heat pumps with a coefficient of performance (COP) of 4.3.</p><h3>Graphical abstract</h3>\u0000<div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":494,"journal":{"name":"Biotechnology for Biofuels","volume":"17 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://biotechnologyforbiofuels.biomedcentral.com/counter/pdf/10.1186/s13068-024-02573-7","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142329389","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Divergent roles of ADP-ribosylation factor GTPase-activating proteins in lignocellulose utilization of Trichoderma guizhouense NJAU4742","authors":"Tuo Li,&nbsp;Qin Wang,&nbsp;Yang Liu,&nbsp;Jiaguo Wang,&nbsp;Han Zhu,&nbsp;Linhua Cao,&nbsp;Dongyang Liu,&nbsp;Qirong Shen","doi":"10.1186/s13068-024-02570-w","DOIUrl":"10.1186/s13068-024-02570-w","url":null,"abstract":"<div><h3>Background</h3><p>The ability of lignocellulose degradation for filamentous fungi is always attributed to their efficient CAZymes system with broader applications in bioenergy development. ADP-ribosylation factor GTPase-activating proteins (Arf-GAPs), pivotal in fungal morphogenesis, lack comprehensive studies on their regulatory mechanisms in lignocellulose utilization.</p><h3>Results</h3><p>Here, the orthologs (<i>Tg</i>Glo3 and <i>Tg</i>Gcs1) of Arf-GAPs in <i>S. cerevisiae</i> were characterized in <i>Trichoderma guizhouense</i> NJAU4742. The results indicated that overexpression of <i>Tggcs1</i> (OE-<i>Tggcs1</i>) enhanced the lignocellulose utilization, whereas increased expression of <i>Tgglo3</i> (OE-<i>Tgglo3</i>) elicited antithetical responses. On the fourth day of fermentation with rice straw as the sole carbon source, the activities of endoglucanase, cellobiohydrolase, xylanase, and filter paper of the wild-type strain (WT) reached 8.20 U mL⁻¹, 4.42 U mL⁻¹, 14.10 U mL⁻¹, and 3.56 U mL⁻¹, respectively. Compared to WT, the four enzymes activities of OE-<i>Tggcs1</i> increased by 7.93%, 6.11%, 9.08%, and 12.92%, respectively, while those decreased to varying degrees of OE-<i>Tgglo3</i>. During the nutritional growth, OE-<i>Tgglo3</i> resulted in the hyphal morphology characterized by sparsity and constriction, while OE-<i>Tggcs1</i> led to a notable increase in vacuole volume. In addition, OE-<i>Tggcs1</i> exhibited higher transport efficiencies for glucose and cellobiose thereby sustaining robust cellular metabolic rates. Further investigations revealed that <i>Tgglo3</i> and <i>Tggcs1</i> differentially regulated the transcription level of a dynamin-like GTPase gene (<i>Tggtp</i>), eliciting distinct redox states and apoptotic reaction, thus orchestrating the cellular response to lignocellulose utilization.</p><h3>Conclusions</h3><p>Overall, these findings underscored the significance of <i>Tg</i>Arf-GAPs as pivotal regulators in lignocellulose utilization and provided initial insights into their differential modulation of downstream targets.</p></div>","PeriodicalId":494,"journal":{"name":"Biotechnology for Biofuels","volume":"17 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://biotechnologyforbiofuels.biomedcentral.com/counter/pdf/10.1186/s13068-024-02570-w","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142253567","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Engineering Escherichia coli for utilization of PET degraded ethylene glycol as sole feedstock","authors":"Junxi Chi,&nbsp;Pengju Wang,&nbsp;Yidan Ma,&nbsp;Xingmiao Zhu,&nbsp;Leilei Zhu,&nbsp;Ming Chen,&nbsp;Changhao Bi,&nbsp;Xueli Zhang","doi":"10.1186/s13068-024-02568-4","DOIUrl":"10.1186/s13068-024-02568-4","url":null,"abstract":"<div><p>From both economic and environmental perspectives, ethylene glycol, the principal constituent in the degradation of PET, emerges as an optimal feedstock for microbial cell factories. Traditional methods for constructing <i>Escherichia coli</i> chassis cells capable of utilizing ethylene glycol as a non-sugar feedstock typically involve overexpressing the genes <i>fucO</i> and <i>aldA</i>. However, these approaches have not succeeded in enabling the exclusive use of ethylene glycol as the sole source of carbon and energy for growth. Through ultraviolet radiation-induced mutagenesis and subsequent laboratory adaptive evolution, an EG02 strain emerged from <i>E. coli</i> MG1655 capable of utilizing ethylene glycol as its sole carbon and energy source, demonstrating an uptake rate of 8.1 ± 1.3 mmol/gDW h. Comparative transcriptome analysis guided reverse metabolic engineering, successfully enabling four wild-type <i>E. coli</i> strains to metabolize ethylene glycol exclusively. This was achieved through overexpression of the <i>gcl</i>, <i>hyi</i>, <i>glxR</i>, and <i>glxK</i> genes. Notably, the engineered <i>E. coli</i> chassis cells efficiently metabolized the 87 mM ethylene glycol found in PET enzymatic degradation products following 72 h of fermentation. This work presents a practical solution for recycling ethylene glycol from PET waste degradation products, demonstrating that simply adding M9 salts can effectively convert them into viable raw materials for <i>E. coli</i> cell factories. Our findings also emphasize the significant roles of genes associated with the glycolate and glyoxylate degradation I pathway in the metabolic utilization of ethylene glycol, an aspect frequently overlooked in previous research.</p></div>","PeriodicalId":494,"journal":{"name":"Biotechnology for Biofuels","volume":"17 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://biotechnologyforbiofuels.biomedcentral.com/counter/pdf/10.1186/s13068-024-02568-4","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142206069","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Discovery of alkaline laccases from basidiomycete fungi through machine learning-based approach","authors":"Xing Wan,&nbsp;Sazzad Shahrear,&nbsp;Shea Wen Chew,&nbsp;Francisco Vilaplana,&nbsp;Miia R. Mäkelä","doi":"10.1186/s13068-024-02566-6","DOIUrl":"10.1186/s13068-024-02566-6","url":null,"abstract":"<div><h3>Background</h3><p>Laccases can oxidize a broad spectrum of substrates, offering promising applications in various sectors, such as bioremediation, biomass fractionation in future biorefineries, and synthesis of biochemicals and biopolymers. However, laccase discovery and optimization with a desirable pH optimum remains a challenge due to the labor-intensive and time-consuming nature of the traditional laboratory methods.</p><h3>Results</h3><p>This study presents a machine learning (ML)-integrated approach for predicting pH optima of basidiomycete fungal laccases, utilizing a small, curated dataset against a vast metagenomic data. Comparative computational analyses unveiled the structural and pH-dependent solubility differences between acidic and neutral-alkaline laccases, helping us understand the molecular bases of enzyme pH optimum. The pH profiling of the two ML-predicted alkaline laccase candidates from the basidiomycete fungus <i>Lepista nuda</i> further validated our computational approach, showing the accuracy of this comprehensive method.</p><h3>Conclusions</h3><p>This study uncovers the efficacy of ML in the prediction of enzyme pH optimum from minimal datasets, marking a significant step towards harnessing computational tools for systematic screening of enzymes for biotechnology applications.</p><h3>Graphical Abstract</h3>\u0000<div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":494,"journal":{"name":"Biotechnology for Biofuels","volume":"17 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://biotechnologyforbiofuels.biomedcentral.com/counter/pdf/10.1186/s13068-024-02566-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142169810","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Clostridium autoethanogenum alters cofactor synthesis, redox metabolism, and lysine-acetylation in response to elevated H2:CO feedstock ratios for enhancing carbon capture efficiency","authors":"Megan E. Davin,&nbsp;R. Adam Thompson,&nbsp;Richard J. Giannone,&nbsp;Lucas W. Mendelson,&nbsp;Dana L. Carper,&nbsp;Madhavi Z. Martin,&nbsp;Michael E. Martin,&nbsp;Nancy L. Engle,&nbsp;Timothy J. Tschaplinski,&nbsp;Steven D. Brown,&nbsp;Robert L. Hettich","doi":"10.1186/s13068-024-02554-w","DOIUrl":"10.1186/s13068-024-02554-w","url":null,"abstract":"<div><h3>Background</h3><p><i>Clostridium autoethanogenum</i> is an acetogenic bacterium that autotrophically converts carbon monoxide (CO) and carbon dioxide (CO₂) gases into bioproducts and fuels via the Wood–Ljungdahl pathway (WLP). To facilitate overall carbon capture efficiency, the reaction stoichiometry requires supplementation of hydrogen at an increased ratio of H₂:CO to maximize CO₂ utilization; however, the molecular details and thus the ability to understand the mechanism of this supplementation are largely unknown.</p><h3>Results</h3><p>In order to elucidate the microbial physiology and fermentation where at least 75% of the carbon in ethanol comes from CO₂, we established controlled chemostats that facilitated a novel and high (11:1) H₂:CO uptake ratio. We compared and contrasted proteomic and metabolomics profiles to replicate continuous stirred tank reactors (CSTRs) at the same growth rate from a lower (5:1) H₂:CO condition where ~ 50% of the carbon in ethanol is derived from CO₂. Our hypothesis was that major changes would be observed in the hydrogenases and/or redox-related proteins and the WLP to compensate for the elevated hydrogen feed gas. Our analyses did reveal protein abundance differences between the two conditions largely related to reduction–oxidation (redox) pathways and cofactor biosynthesis, but the changes were more minor than we would have expected. While the Wood–Ljungdahl pathway proteins remained consistent across the conditions, other post-translational regulatory processes, such as lysine-acetylation, were observed and appeared to be more important for fine-tuning this carbon metabolism pathway. Metabolomic analyses showed that the increase in H₂:CO ratio drives the organism to higher carbon dioxide utilization resulting in lower carbon storages and accumulated fatty acid metabolite levels.</p><h3>Conclusions</h3><p>This research delves into the intricate dynamics of carbon fixation in <i>C. autoethanogenum</i>, examining the influence of highly elevated H₂:CO ratios on metabolic processes and product outcomes. The study underscores the significance of optimizing gas feed composition for enhanced industrial efficiency, shedding light on potential mechanisms, such as post-translational modifications (PTMs), to fine-tune enzymatic activities and improve desired product yields.</p></div>","PeriodicalId":494,"journal":{"name":"Biotechnology for Biofuels","volume":"17 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://biotechnologyforbiofuels.biomedcentral.com/counter/pdf/10.1186/s13068-024-02554-w","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142123085","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The impact of the carbohydrate-binding module on how a lytic polysaccharide monooxygenase modifies cellulose fibers","authors":"Fredrik G. Støpamo,&nbsp;Irina Sulaeva,&nbsp;David Budischowsky,&nbsp;Jenni Rahikainen,&nbsp;Kaisa Marjamaa,&nbsp;Kristiina Kruus,&nbsp;Antje Potthast,&nbsp;Vincent G. H. Eijsink,&nbsp;Anikó Várnai","doi":"10.1186/s13068-024-02564-8","DOIUrl":"10.1186/s13068-024-02564-8","url":null,"abstract":"<div><h3>Background</h3><p>In recent years, lytic polysaccharide monooxygenases (LPMOs) that oxidatively cleave cellulose have gained increasing attention in cellulose fiber modification. LPMOs are relatively small copper-dependent redox enzymes that occur as single domain proteins but may also contain an appended carbohydrate-binding module (CBM). Previous studies have indicated that the CBM “immobilizes” the LPMO on the substrate and thus leads to more localized oxidation of the fiber surface. Still, our understanding of how LPMOs and their CBMs modify cellulose fibers remains limited.</p><h3>Results</h3><p>Here, we studied the impact of the CBM on the fiber-modifying properties of <i>Nc</i>AA9C, a two-domain family AA9 LPMO from <i>Neurospora crassa</i>, using both biochemical methods as well as newly developed multistep fiber dissolution methods that allow mapping LPMO action across the fiber, from the fiber surface to the fiber core. The presence of the CBM in <i>Nc</i>AA9C improved binding towards amorphous (PASC), natural (Cell I), and alkali-treated (Cell II) cellulose, and the CBM was essential for significant binding of the non-reduced LPMO to Cell I and Cell II. Substrate binding of the catalytic domain was promoted by reduction, allowing the truncated CBM-free <i>Nc</i>AA9C to degrade Cell I and Cell II, albeit less efficiently and with more autocatalytic enzyme degradation compared to the full-length enzyme. The sequential dissolution analyses showed that cuts by the CBM-free enzyme are more evenly spread through the fiber compared to the CBM-containing full-length enzyme and showed that the truncated enzyme can penetrate deeper into the fiber, thus giving relatively more oxidation and cleavage in the fiber core.</p><h3>Conclusions</h3><p>These results demonstrate the capability of LPMOs to modify cellulose fibers from surface to core and reveal how variation in enzyme modularity can be used to generate varying cellulose-based materials. While the implications of these findings for LPMO-based cellulose fiber engineering remain to be explored, it is clear that the presence of a CBM is an important determinant of the three-dimensional distribution of oxidation sites in the fiber.</p></div>","PeriodicalId":494,"journal":{"name":"Biotechnology for Biofuels","volume":"17 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://biotechnologyforbiofuels.biomedcentral.com/counter/pdf/10.1186/s13068-024-02564-8","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142045148","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Furfural tolerance of mutant Saccharomyces cerevisiae selected via ionizing radiation combined with adaptive laboratory evolution","authors":"Junle Ren,&nbsp;Miaomiao Zhang,&nbsp;Xiaopeng Guo,&nbsp;Xiang Zhou,&nbsp;Nan Ding,&nbsp;Cairong Lei,&nbsp;Chenglin Jia,&nbsp;Yajuan Wang,&nbsp;Jingru Zhao,&nbsp;Ziyi Dong,&nbsp;Dong Lu","doi":"10.1186/s13068-024-02562-w","DOIUrl":"10.1186/s13068-024-02562-w","url":null,"abstract":"<div><h3>Background</h3><p>Lignocellulose is a renewable and sustainable resource used to produce second-generation biofuel ethanol to cope with the resource and energy crisis. Furfural is the most toxic inhibitor of <i>Saccharomyces cerevisiae</i> cells produced during lignocellulose treatment, and can reduce the ability of <i>S. cerevisiae</i> to utilize lignocellulose, resulting in low bioethanol yield. In this study, multiple rounds of progressive ionizing radiation was combined with adaptive laboratory evolution to improve the furfural tolerance of <i>S. cerevisiae</i> and increase the yield of ethanol.</p><h3>Results</h3><p>In this study, the strategy of multiple rounds of progressive X-ray radiation combined with adaptive laboratory evolution significantly improved the furfural tolerance of brewing yeast. After four rounds of experiments, four mutant strains resistant to high concentrations of furfural were obtained (SCF-R1, SCF-R2, SCF-R3, and SCF-R4), with furfural tolerance concentrations of 4.0, 4.2, 4.4, and 4.5 g/L, respectively. Among them, the mutant strain SCF-R4 obtained in the fourth round of radiation had a cellular malondialdehyde content of 49.11 nmol/mg after 3 h of furfural stress, a weakening trend in mitochondrial membrane potential collapse, a decrease in accumulated reactive oxygen species, and a cell death rate of 12.60%, showing better cell membrane integrity, stable mitochondrial function, and an improved ability to limit reactive oxygen species production compared to the other mutant strains and the wild-type strain. In a fermentation medium containing 3.5 g/L furfural, the growth lag phase of the SCF-R4 mutant strain was shortened, and its growth ability significantly improved. After 96 h of fermentation, the ethanol production of the mutant strain SCF-R4 was 1.86 times that of the wild-type, indicating that with an increase in the number of irradiation rounds, the furfural tolerance of the mutant strain SCF-R4 was effectively enhanced. In addition, through genome-transcriptome analysis, potential sites related to furfural detoxification were identified, including <i>GAL7</i>, <i>MAE1</i>, <i>PDC6</i>, <i>HXT1</i>, <i>AUS1</i>, and <i>TPK3</i>.</p><h3>Conclusions</h3><p>These results indicate that multiple rounds of progressive X-ray radiation combined with adaptive laboratory evolution is an effective mutagenic strategy for obtaining furfural-tolerant mutants and that it has the potential to tap genes related to the furfural detoxification mechanism.</p><h3>Graphical Abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":494,"journal":{"name":"Biotechnology for Biofuels","volume":"17 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://biotechnologyforbiofuels.biomedcentral.com/counter/pdf/10.1186/s13068-024-02562-w","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142038005","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}