Biotechnology for Biofuels最新文献

{"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}

{"title":"Rapid measurement of soluble xylo-oligomers using near-infrared spectroscopy (NIRS) and multivariate statistics: calibration model development and practical approaches to model optimization","authors":"Zofia Tillman,&nbsp;Kevin Gray,&nbsp;Edward Wolfrum","doi":"10.1186/s13068-024-02558-6","DOIUrl":"10.1186/s13068-024-02558-6","url":null,"abstract":"<div><h3>Background</h3><p>Rapid monitoring of biomass conversion processes using techniques such as near-infrared (NIR) spectroscopy can be substantially quicker and less labor-, resource-, and energy-intensive than conventional measurement techniques such as gas or liquid chromatography (GC or LC) due to the lack of solvents and preparation methods, as well as removing the need to transfer samples to an external lab for analytical evaluation. The purpose of this study was to determine the feasibility of rapid monitoring of a biomass conversion process using NIR spectroscopy combined with multivariate statistical modeling, and to examine the impact of (1) subsetting the samples in the original dataset by process location and (2) reducing the spectral range used in the calibration model on model performance.</p><h3>Results</h3><p>We develop multivariate calibration models for the concentrations of soluble xylo-oligosaccharides (XOS), monomeric xylose, and total solids at multiple points in a biomass conversion process which produces and then purifies XOS compounds from sugar cane bagasse. A single model using samples from multiple locations in the process stream showed acceptable performance as measured by standard statistical measures. However, compared to the single model, we show that separate models built by segregating the calibration samples according to process location show improved performance. We also show that combining an understanding of the sample spectra with simple multivariate analysis tools can result in a calibration model with a substantially smaller spectral range that provides essentially equal performance to the full-range model.</p><h3>Conclusions</h3><p>We demonstrate that real-time monitoring of soluble xylo-oligosaccharides (XOS), monomeric xylose, and total solids concentration at multiple points in a process stream using NIR spectroscopy coupled with multivariate statistics is feasible. Segregation of sample populations by process location improves model performance. Models using a reduced spectral range containing the most relevant spectral signatures show very similar performance to the full-range model, reinforcing the importance of performing robust exploratory data analysis before beginning multivariate modeling.</p></div>","PeriodicalId":494,"journal":{"name":"Biotechnology for Biofuels","volume":"17 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://biotechnologyforbiofuels.biomedcentral.com/counter/pdf/10.1186/s13068-024-02558-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141980182","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":"Bubbling insights: unveiling the true sophorolipid biosynthetic pathway by Starmerella bombicola","authors":"Sophie L. K. W. Roelants,&nbsp;Stijn Bovijn,&nbsp;Elvira Bytyqi,&nbsp;Nicolas de Fooz,&nbsp;Goedele Luyten,&nbsp;Martijn Castelein,&nbsp;Thibo Van de Craen,&nbsp;Zhoujian Diao,&nbsp;Karolien Maes,&nbsp;Tom Delmulle,&nbsp;Maarten De Mol,&nbsp;Sofie L. De Maeseneire,&nbsp;Bart Devreese,&nbsp;Wim K. Soetaert","doi":"10.1186/s13068-024-02557-7","DOIUrl":"10.1186/s13068-024-02557-7","url":null,"abstract":"<div><h3>Background</h3><p>The yeast <i>Starmerella bombicola</i> is renowned for its highly efficient sophorolipid production, reaching titers and productivities of (over) 200 g/L and 2 g/(L h), respectively. This inherent efficiency has led to the commercialization of sophorolipids. While the sophorolipid biosynthetic pathway has been elucidated a few years ago, in this study, it is revisited and true key intermediates are revealed.</p><h3>Results</h3><p>Recently, <i>Starmerella bombicola</i> strains developed and evaluated in the past were reevaluated unveiling unexpected findings. The AT enzyme encoded in the sophorolipid biosynthetic gene cluster is the only described enzyme known to acetylate sophorolipids, while the SBLE enzyme encoded by the <i>SBLE</i> gene is described to catalyze the conversion of (acetylated) acidic sophorolipids into lactonic sophorolipids. A double knockout of both genes was described to result in the generation of bolaform sophorolipids. However, new experiments performed with respective <i>S. bombicola</i> strains <i>Δsble</i>, <i>Δat Δsble</i>, and ∆<i>at</i> revealed inconsistencies with the current understanding of the SL pathway. It was observed that the ∆<i>sble</i> strain produces mainly bolaform sophorolipids with higher acetylation degrees instead of acidic sophorolipids. Furthermore, the ∆<i>at</i> strain produces predominantly bolaform sophorolipids and lactonic sophorolipids with lower acetylation degrees, while the ∆<i>at</i> ∆<i>sble</i> strain predominantly produces bolaform sophorolipids with lower acetylation degrees. These results indicate that the AT enzyme is not the only enzyme responsible for acetylation of sophorolipids, while the SBLE enzyme performs an intramolecular transesterification reaction on bolaform glycolipids instead of an esterification reaction on acidic sophorolipids. These findings, together with recent in vitro data, led us to revise the sophorolipid biosynthetic pathway.</p><h3>Conclusions</h3><p>Bolaform sophorolipids instead of acidic sophorolipids are the key intermediates in the biosynthetic pathway towards lactonic sophorolipids. Bolaform sophorolipids are found in very small amounts in extracellular <i>S. bombicola</i> wild type broths as they are very efficiently converted into lactonic sophorolipids, while acidic sophorolipids build up as they cannot be converted. Furthermore, acetylation of sophorolipids is not exclusively performed by the AT enzyme encoded in the sophorolipid biosynthetic gene cluster and acetylation of bolaform sophorolipids promotes their transesterification. These findings led to the revision of the industrially relevant sophorolipid biosynthetic pathway.</p></div>","PeriodicalId":494,"journal":{"name":"Biotechnology for Biofuels","volume":"17 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://biotechnologyforbiofuels.biomedcentral.com/counter/pdf/10.1186/s13068-024-02557-7","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141984111","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":"Establishment of Saccharomyces cerevisiae as a cell factory for efficient de novo production of monogalactosyldiacylglycerol","authors":"Xiaosong Gu,&nbsp;Yumei Shi,&nbsp;Changxin Luo,&nbsp;Jintao Cheng","doi":"10.1186/s13068-024-02560-y","DOIUrl":"10.1186/s13068-024-02560-y","url":null,"abstract":"<div><p>Monogalactosyldiacylglycerol (MGDG), a predominant photosynthetic membrane lipid derived from plants and microalgae, has important applications in feed additives, medicine, and other fields. The low content and various structural stereoselectivity differences of MGDG in plants limited the biological extraction or chemical synthesis of MGDG, resulting in a supply shortage of monogalactosyldiacylglycerol with a growing demand. Herein, we established <i>Saccharomyces cerevisiae</i> as a cell factory for efficient de novo production of monogalactosyldiacylglycerol for the first time. Heterologous production of monogalactosyldiacylglycerol was achieved by overexpression of codon-optimized monogalactosyldiacylglycerol synthase gene <i>MGD1</i>, the key Kennedy pathway genes (i.e. <i>GAT1</i>, <i>ICT1</i>, and <i>PAH1</i>), and multi-copy integration of the <i>MGD1</i> expression cassette. The final engineered strain (MG-8) was capable of producing monogalactosyldiacylglycerol with titers as high as 16.58 nmol/mg DCW in a shake flask and 103.2 nmol/mg DCW in a 5 L fed-batch fermenter, respectively. This is the first report of heterologous biosynthesis of monogalactosyldiacylglycerol in microorganisms, which will provide a favorable reference for study on heterologous production of monogalactosyldiacylglycerol in yeasts.</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":"2024-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://biotechnologyforbiofuels.biomedcentral.com/counter/pdf/10.1186/s13068-024-02560-y","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141918334","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":"Efficiency of acetate-based isopropanol synthesis in Escherichia coli W is controlled by ATP demand","authors":"Regina Kutscha,&nbsp;Tamara Tomin,&nbsp;Ruth Birner-Gruenberger,&nbsp;Pavlos Stephanos Bekiaris,&nbsp;Steffen Klamt,&nbsp;Stefan Pflügl","doi":"10.1186/s13068-024-02534-0","DOIUrl":"10.1186/s13068-024-02534-0","url":null,"abstract":"<div><h3>Background</h3><p>Due to increasing ecological concerns, microbial production of biochemicals from sustainable carbon sources like acetate is rapidly gaining importance. However, to successfully establish large-scale production scenarios, a solid understanding of metabolic driving forces is required to inform bioprocess design. To generate such knowledge, we constructed isopropanol-producing <i>Escherichia coli</i> W strains.</p><h3>Results</h3><p>Based on strain screening and metabolic considerations, a 2-stage process was designed, incorporating a growth phase followed by a nitrogen-starvation phase. This process design yielded the highest isopropanol titers on acetate to date (13.3 g L⁻¹). Additionally, we performed shotgun and acetylated proteomics, and identified several stress conditions in the bioreactor scenarios, such as acid stress and impaired sulfur uptake. Metabolic modeling allowed for an in-depth characterization of intracellular flux distributions, uncovering cellular demand for ATP and acetyl-CoA as limiting factors for routing carbon toward the isopropanol pathway. Moreover, we asserted the importance of a balance between fluxes of the NADPH-providing isocitrate dehydrogenase (ICDH) and the product pathway.</p><h3>Conclusions</h3><p>Using the newly gained system-level understanding for isopropanol production from acetate, we assessed possible engineering approaches and propose process designs to maximize production. Collectively, our work contributes to the establishment and optimization of acetate-based bioproduction systems.</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":"2024-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11302359/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141895087","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":"Exploring the stress response mechanisms to 2-phenylethanol conferred by Pdr1p mutation in Saccharomyces cerevisiae","authors":"Huili Xia,&nbsp;Na Song,&nbsp;Daoqi Liu,&nbsp;Rong Zhou,&nbsp;Lingling Shangguan,&nbsp;Xiong Chen,&nbsp;Jun Dai","doi":"10.1186/s13068-024-02559-5","DOIUrl":"10.1186/s13068-024-02559-5","url":null,"abstract":"<div><h3>Background</h3><p>The 2-phenylethanol (2-PE) tolerance phenotype is crucial to the production of 2-PE, and Pdr1p mutation can significantly increase the tolerance of 2-PE in <i>Saccharomyces cerevisiae</i>. However, its underlying molecular mechanisms are still unclear, hindering the rational design of superior 2-PE tolerance performance.</p><h3>Results</h3><p>Here, the physiology and biochemistry of the <i>PDR1</i>_862 and 5D strains were analyzed. At 3.5 g/L 2-PE, the ethanol concentration of <i>PDR1</i>_862 decreased by 21%, and the 2-PE production of <i>PDR1</i>_862 increased by 16% than those of 5D strain. Transcriptome analysis showed that at 2-PE stress, Pdr1p mutation increased the expression of genes involved in the Ehrlich pathway. In addition, Pdr1p mutation attenuated sulfur metabolism and enhanced the one-carbon pool by folate to resist 2-PE stress. These metabolic pathways were closely associated with amino acids metabolism. Furthermore, at 3.5 g/L 2-PE, the free amino acids content of <i>PDR1</i>_862 decreased by 31% than that of 5D strain, among the free amino acids, cysteine was key amino acid for the enhancement of 2-PE stress tolerance conferred by Pdr1p mutation.</p><h3>Conclusions</h3><p>The above results indicated that Pdr1p mutation enhanced the Ehrlich pathway to improve 2-PE production of <i>S. cerevisiae</i>, and Pdr1p mutation altered the intracellular amino acids contents, in which cysteine might be a biomarker in response to Pdr1p mutation under 2-PE stress. The findings help to elucidate the molecular mechanisms for 2-PE stress tolerance by Pdr1p mutation in <i>S. cerevisiae</i>, identify key metabolic pathway responsible for 2-PE stress tolerance.</p></div>","PeriodicalId":494,"journal":{"name":"Biotechnology for Biofuels","volume":"17 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11295549/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141876928","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":"Strain and model development for auto- and heterotrophic 2,3-butanediol production using Cupriavidus necator H16","authors":"Janek R. Weiler,&nbsp;Nikolai Jürgensen,&nbsp;Monica Cornejo Infante,&nbsp;Melanie T. Knoll,&nbsp;Johannes Gescher","doi":"10.1186/s13068-024-02549-7","DOIUrl":"10.1186/s13068-024-02549-7","url":null,"abstract":"<div><p>The production of platform chemicals from renewable energy sources is a crucial step towards a post-fossil economy. This study reports on the production of acetoin and 2,3-butanediol heterotrophically with fructose as substrate and autotrophically from CO₂ as carbon source, H₂ as electron donor and O₂ as electron acceptor with <i>Cupriavidus necator.</i> In a previous study, the strain was developed for the production of acetoin with high carbon efficiency. Acetoin can serve as a precursor for the synthesis of 2,3-butanediol by the integration of a butanediol dehydrogenase. In this study, different plasmid backbones and butanediol dehydrogenases were evaluated regarding efficiency for CO₂-based 2,3-butanediol production. The developed strain utilizes the pBBR1 plasmid bearing a 2,3-butanediol dehydrogenase from <i>Enterobacter cloacae</i> and is characterized by 2,3-butanediol as the main product and a heterotrophic total product yield of 88.11%, an autotrophic volumetric productivity of 39.45 mg L⁻¹ h⁻¹, a total product carbon yield of 81.6%, an H₂ efficiency of 33.46%, and a specific productivity of 0.016 g product per gram of biomass per hour. In addition, a mathematical model was developed to simulate the processes under these conditions. With this model, it was possible to calculate productivities and substrate usage at distinct time points of the production processes and calculate productivities and substrate usage with high resolution which will be useful in future applications.</p></div>","PeriodicalId":494,"journal":{"name":"Biotechnology for Biofuels","volume":"17 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11290209/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141857355","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":"Metabolic and tolerance engineering of Komagataella phaffii for 2-phenylethanol production through genome-wide scanning","authors":"Lijing Sun,&nbsp;Ying Gao,&nbsp;Renjie Sun,&nbsp;Ling Liu,&nbsp;Liangcai Lin,&nbsp;Cuiying Zhang","doi":"10.1186/s13068-024-02536-y","DOIUrl":"10.1186/s13068-024-02536-y","url":null,"abstract":"<div><h3>Background</h3><p>2-Phenylethanol (2-PE) is one of the most widely used spices. Recently, 2-PE has also been considered a potential aviation fuel booster. However, the lack of scientific understanding of the 2-PE biosynthetic pathway and the cellular response to 2-PE cytotoxicity are the most important obstacles to the efficient biosynthesis of 2-PE.</p><h3>Results</h3><p>Here, metabolic engineering and tolerance engineering strategies were used to improve the production of 2-PE in <i>Komagataella phaffii</i>. First, the endogenous genes encoding the amino acid permease <i>GAP1</i>, aminotransferase <i>AAT2</i>, phenylpyruvate decarboxylase <i>KDC2</i>, and aldehyde dehydrogenase <i>ALD4</i> involved in the Ehrlich pathway and the 2-PE stress response gene <i>NIT1</i> in <i>K. phaffii</i> were screened and characterized via comparative transcriptome analysis. Subsequently, metabolic engineering was employed to gradually reconstruct the 2-PE biosynthetic pathway, and the engineered strain S43 was obtained, which produced 2.98 g/L 2-PE in shake flask. Furthermore, transcriptional profiling analyses were utilized to screen for novel potential tolerance elements. Our results demonstrated that cells with knockout of the <i>PDR12</i> and <i>C4R2I5</i> genes exhibited a significant increase in 2-PE tolerance. To confirm the practical applications of these results, deletion of the <i>PDR12</i> and <i>C4R2I5</i> genes in the hyper 2-PE producing strain S43 dramatically increased the production of 2-PE by 18.12%, and the production was 3.54 g/L.</p><h3>Conclusion</h3><p>This is the highest production of 2-PE produced by <i>K. phaffii</i> via <span>l</span>-phenylalanine conversion. These identified <i>K. phaffii</i> endogenous elements are highly conserved in other yeast species, suggesting that manipulation of these homologues might be a useful strategy for improving aromatic alcohol production. These results also enrich the understanding of aromatic compound biosynthetic pathways and 2-PE tolerance, and provide new elements and strategies for the synthesis of aromatic compounds by microbial cell factories.</p></div>","PeriodicalId":494,"journal":{"name":"Biotechnology for Biofuels","volume":"17 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://biotechnologyforbiofuels.biomedcentral.com/counter/pdf/10.1186/s13068-024-02536-y","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141741692","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}