Biotechnology for Biofuels最新文献

{"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}

{"title":"A scalable, chromatography-free, biocatalytic method to produce the xyloglucan heptasaccharide XXXG","authors":"Andrew M. Rodd,&nbsp;William M. Mawhinney,&nbsp;Harry Brumer","doi":"10.1186/s13068-024-02563-9","DOIUrl":"10.1186/s13068-024-02563-9","url":null,"abstract":"<div><p>Xyloglucan oligosaccharides (XyGOs) are highly branched, complex carbohydrates with a variety of chemical and biotechnological applications. Due to the regular repeating pattern of sidechain substitution of the xyloglucan backbone, well-defined XyGOs are readily accessed for analytical and preparative purposes by specific hydrolysis of the polysaccharide with <i>endo</i>-glucanases. To broaden the application potential of XyGOs, we present here an optimized, scalable method to access large quantities of galactosylated XyGOs by treatment of the bulk agricultural by-product, tamarind kernel powder (TKP), with a highly specific <i>endo</i>-xyloglucanase at high-solids content. Subsequent β-galactosidase treatment reduced XyGO complexity to produce exclusively the branched heptasaccharide XXXG (Xyl₃Glc₄: [α-D-Xyl<i>p</i>-(1 → 6)]-β-D-Glc<i>p</i>-(1 → 4)-[α-D-Xyl<i>p</i>-(1 → 6)]-β-D-Glc<i>p</i>-(1 → 4)-[α-D-Xyl<i>p</i>-(1 → 6)]-β-D-Glc<i>p</i>-(1 → 4)-D-Glc<i>p</i>). The challenge of removing the co-product galactose was overcome by fermentation with baker’s yeast, thereby avoiding chromatography and other fractionation steps to yield highly pure XXXG. This simplified approach employs many of the core concepts of green chemistry and engineering, enables facile production of 100 g quantities of XyGOs and XXXG for laboratory use, and serves as a guide to further production scale-up for applications, including as prebiotics, plant growth effectors and elicitors, and building blocks for glycoconjugate synthesis.</p></div>","PeriodicalId":494,"journal":{"name":"Biotechnology for Biofuels","volume":"17 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://biotechnologyforbiofuels.biomedcentral.com/counter/pdf/10.1186/s13068-024-02563-9","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142010113","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":"Microbial conversion of ethanol to high-value products: progress and challenges","authors":"Manman Sun,&nbsp;Alex Xiong Gao,&nbsp;Xiuxia Liu,&nbsp;Zhonghu Bai,&nbsp;Peng Wang,&nbsp;Rodrigo Ledesma-Amaro","doi":"10.1186/s13068-024-02546-w","DOIUrl":"10.1186/s13068-024-02546-w","url":null,"abstract":"<div><p>Industrial biotechnology heavily relies on the microbial conversion of carbohydrate substrates derived from sugar- or starch-rich crops. This dependency poses significant challenges in the face of a rising population and food scarcity. Consequently, exploring renewable, non-competing carbon sources for sustainable bioprocessing becomes increasingly important. Ethanol, a key C2 feedstock, presents a promising alternative, especially for producing acetyl-CoA derivatives. In this review, we offer an in-depth analysis of ethanol's potential as an alternative carbon source, summarizing its distinctive characteristics when utilized by microbes, microbial ethanol metabolism pathway, and microbial responses and tolerance mechanisms to ethanol stress. We provide an update on recent progress in ethanol-based biomanufacturing and ethanol biosynthesis, discuss current challenges, and outline potential research directions to guide future advancements in this field. The insights presented here could serve as valuable theoretical support for researchers and industry professionals seeking to harness ethanol's potential for the production of high-value products.</p><h3>Graphic 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":"2024-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://biotechnologyforbiofuels.biomedcentral.com/counter/pdf/10.1186/s13068-024-02546-w","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142006043","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":"Hydrothermal conditioning of oleaginous yeast cells to enable recovery of lipids as potential drop-in fuel precursors","authors":"Shivali Banerjee,&nbsp;Bruce S. Dien,&nbsp;Vijay Singh","doi":"10.1186/s13068-024-02561-x","DOIUrl":"10.1186/s13068-024-02561-x","url":null,"abstract":"<div><h3>Background</h3><p>Lipids produced using oleaginous yeast cells are an emerging feedstock to manufacture commercially valuable oleochemicals ranging from pharmaceuticals to lipid-derived biofuels. Production of biofuels using oleaginous yeast is a multistep procedure that requires yeast cultivation and harvesting, lipid recovery, and conversion of the lipids to biofuels. The quantitative recovery of the total intracellular lipid from the yeast cells is a critical step during the development of a bioprocess. Their rigid cell walls often make them resistant to lysis. The existing methods include mechanical, chemical, biological and thermochemical lysis of yeast cell walls followed by solvent extraction. In this study, an aqueous thermal pretreatment was explored as a method for lysing the cell wall of the oleaginous yeast <i>Rhodotorula toruloides</i> for lipid recovery.</p><h3>Results</h3><p>Hydrothermal pretreatment for 60 min at 121 °C with a dry cell weight of 7% (w/v) in the yeast slurry led to a recovery of 84.6 ± 3.2% (w/w) of the total lipids when extracted with organic solvents. The conventional sonication and acid-assisted thermal cell lysis led to a lipid recovery yield of 99.8 ± 0.03% (w/w) and 109.5 ± 1.9% (w/w), respectively. The fatty acid profiles of the hydrothermally pretreated cells and freeze-dried control were similar, suggesting that the thermal lysis of the cells did not degrade the lipids.</p><h3>Conclusion</h3><p>This work demonstrates that hydrothermal pretreatment of yeast cell slurry at 121 °C for 60 min is a robust and sustainable method for cell conditioning to extract intracellular microbial lipids for biofuel production and provides a baseline for further scale-up and process integration.</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":"2024-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://biotechnologyforbiofuels.biomedcentral.com/counter/pdf/10.1186/s13068-024-02561-x","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141994009","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}