Biotechnology for Biofuels最新文献

{"title":"Exploring the role of flavin-dependent monooxygenases in the biosynthesis of aromatic compounds","authors":"Tong Shi,&nbsp;Xinxiao Sun,&nbsp;Qipeng Yuan,&nbsp;Jia Wang,&nbsp;Xiaolin Shen","doi":"10.1186/s13068-024-02490-9","DOIUrl":"10.1186/s13068-024-02490-9","url":null,"abstract":"<div><p>Hydroxylated aromatic compounds exhibit exceptional biological activities. In the biosynthesis of these compounds, three types of hydroxylases are commonly employed: cytochrome P450 (CYP450), pterin-dependent monooxygenase (PDM), and flavin-dependent monooxygenase (FDM). Among these, FDM is a preferred choice due to its small molecular weight, stable expression in both prokaryotic and eukaryotic fermentation systems, and a relatively high concentration of necessary cofactors. However, the catalytic efficiency of many FDMs falls short of meeting the demands of large-scale production. Additionally, challenges arise from the limited availability of cofactors and compatibility issues among enzyme components. Recently, significant progress has been achieved in improving its catalytic efficiency, but have not yet detailed and informative viewed so far. Therefore, this review emphasizes the advancements in FDMs for the biosynthesis of hydroxylated aromatic compounds and presents a summary of three strategies aimed at enhancing their catalytic efficiency: (a) Developing efficient enzyme mutants through protein engineering; (b) enhancing the supply and rapid circulation of critical cofactors; (c) facilitating cofactors delivery for enhancing FDMs catalytic efficiency. Furthermore, the current challenges and further perspectives on improving catalytic efficiency of FDMs are also discussed.</p></div>","PeriodicalId":494,"journal":{"name":"Biotechnology for Biofuels","volume":"17 1","pages":""},"PeriodicalIF":6.3,"publicationDate":"2024-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://biotechnologyforbiofuels.biomedcentral.com/counter/pdf/10.1186/s13068-024-02490-9","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140192074","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":"Structural insights into curdlan degradation via a glycoside hydrolase containing a disruptive carbohydrate-binding module","authors":"Tianhang Lv,&nbsp;Juanjuan Feng,&nbsp;Xiaoyu Jia,&nbsp;Cheng Wang,&nbsp;Fudong Li,&nbsp;Hui Peng,&nbsp;Yazhong Xiao,&nbsp;Lin Liu,&nbsp;Chao He","doi":"10.1186/s13068-024-02494-5","DOIUrl":"10.1186/s13068-024-02494-5","url":null,"abstract":"<div><h3>Background</h3><p>Degradation via enzymatic processes for the production of valuable β-1,3-glucooligosaccharides (GOS) from curdlan has attracted considerable interest. CBM6E functions as a curdlan-specific β-1,3-endoglucanase, composed of a glycoside hydrolase family 128 (GH128) module and a carbohydrate-binding module (CBM) derived from family CBM6.</p><h3>Results</h3><p>Crystallographic analyses were conducted to comprehend the substrate specificity mechanism of CBM6E. This unveiled structures of both apo CBM6E and its GOS-complexed form. The GH128 and CBM6 modules constitute a cohesive unit, binding nine glucoside moieties within the catalytic groove in a singular helical conformation. By extending the substrate-binding groove, we engineered CBM6E variants with heightened hydrolytic activities, generating diverse GOS profiles from curdlan. Molecular docking, followed by mutation validation, unveiled the cooperative recognition of triple-helical β-1,3-glucan by the GH128 and CBM6 modules, along with the identification of a novel sugar-binding residue situated within the CBM6 module. Interestingly, supplementing the CBM6 module into curdlan gel disrupted the gel’s network structure, enhancing the hydrolysis of curdlan by specific β-1,3-glucanases.</p><h3>Conclusions</h3><p>This study offers new insights into the recognition mechanism of glycoside hydrolases toward triple-helical β-1,3-glucans, presenting an effective method to enhance endoglucanase activity and manipulate its product profile. Furthermore, it discovered a CBM module capable of disrupting the quaternary structures of curdlan, thereby boosting the hydrolytic activity of curdlan gel when co-incubated with β-1,3-glucanases. These findings hold relevance for developing future enzyme and CBM cocktails useful in GOS production from curdlan degradation.</p></div>","PeriodicalId":494,"journal":{"name":"Biotechnology for Biofuels","volume":"17 1","pages":""},"PeriodicalIF":6.3,"publicationDate":"2024-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://biotechnologyforbiofuels.biomedcentral.com/counter/pdf/10.1186/s13068-024-02494-5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140186597","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 high-yielding 2,5-Dimethylpyrazine synthesis from L-Threonine by reconstructing metabolic pathways and enhancing cofactors regeneration","authors":"Xin-Xin Liu,&nbsp;Yao Wang,&nbsp;Jian-Hui Zhang,&nbsp;Yun-Feng Lu,&nbsp;Zi-Xing Dong,&nbsp;Chao Yue,&nbsp;Xian-Qing Huang,&nbsp;Si-Pu Zhang,&nbsp;Dan-Dan Li,&nbsp;Lun-Guang Yao,&nbsp;Cun-Duo Tang","doi":"10.1186/s13068-024-02487-4","DOIUrl":"10.1186/s13068-024-02487-4","url":null,"abstract":"<div><p>2,5-Dimethylpyrazine (2,5-DMP) is important pharmaceutical raw material and food flavoring agent. Recently, engineering microbes to produce 2,5-DMP has become an attractive alternative to chemical synthesis approach. In this study, metabolic engineering strategies were used to optimize the modified <i>Escherichia coli</i> BL21 (DE3) strain for efficient synthesis of 2,5-DMP using <i>L</i>-threonine dehydrogenase (<i>Ec</i>TDH) from <i>Escherichia coli</i> BL21, NADH oxidase (<i>Eh</i>NOX) from <i>Enterococcus hirae</i>, aminoacetone oxidase (<i>Sc</i>AAO) from <i>Streptococcus cristatus</i> and <i>L</i>-threonine transporter protein (<i>Ec</i>SstT) from <i>Escherichia coli</i> BL21, respectively. We further optimized the reaction conditions for synthesizing 2,5-DMP. In optimized conditions, the modified strain can convert <i>L</i>-threonine to obtain 2,5-DMP with a yield of 2897.30 mg/L. Therefore, the strategies used in this study contribute to the development of high-level cell factories for 2,5-DMP.</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":6.3,"publicationDate":"2024-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://biotechnologyforbiofuels.biomedcentral.com/counter/pdf/10.1186/s13068-024-02487-4","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140159694","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":"Multi-omics analysis reveals novel loci and a candidate regulatory gene of unsaturated fatty acids in soybean (Glycine max (L.) Merr)","authors":"Xunchao Zhao,&nbsp;Yuhang Zhan,&nbsp;Kaiming Li,&nbsp;Yan Zhang,&nbsp;Changjun Zhou,&nbsp;Ming Yuan,&nbsp;Miao Liu,&nbsp;Yongguang Li,&nbsp;Peng Zuo,&nbsp;Yingpeng Han,&nbsp;Xue Zhao","doi":"10.1186/s13068-024-02489-2","DOIUrl":"10.1186/s13068-024-02489-2","url":null,"abstract":"<div><h3>Background</h3><p>Soybean is a major oil crop; the nutritional components of soybean oil are mainly controlled by unsaturated fatty acids (FA). Unsaturated FAs mainly include oleic acid (OA, 18:1), linoleic acid (LLA, 18:2), and linolenic acid (LNA, 18:3). The genetic architecture of unsaturated FAs in soybean seeds has not been fully elucidated, although many independent studies have been conducted. A 3 V multi-locus random single nucleotide polymorphism (SNP)-effect mixed linear model (3VmrMLM) was established to identify quantitative trait loci (QTLs) and QTL-by-environment interactions (QEIs) for complex traits.</p><h3>Results</h3><p>In this study, 194 soybean accessions with 36,981 SNPs were calculated using the 3VmrMLM model. As a result, 94 quantitative trait nucleotides (QTNs) and 19 QEIs were detected using single-environment (QTN) and multi-environment (QEI) methods. Three significant QEIs, namely rs4633292, rs39216169, and rs14264702, overlapped with a significant single-environment QTN.</p><h3>Conclusions</h3><p>For QTNs and QEIs, further haplotype analysis of candidate genes revealed that the <i>Glyma.03G040400</i> and <i>Glyma.17G236700</i> genes were beneficial haplotypes that may be associated with unsaturated FAs. This result provides ideas for the identification of soybean lipid-related genes and provides insights for breeding high oil soybean varieties in the future.</p></div>","PeriodicalId":494,"journal":{"name":"Biotechnology for Biofuels","volume":"17 1","pages":""},"PeriodicalIF":6.3,"publicationDate":"2024-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://biotechnologyforbiofuels.biomedcentral.com/counter/pdf/10.1186/s13068-024-02489-2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140141235","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":"Carbon and energy balance of biotechnological glycolate production from microalgae in a pre-industrial scale flat panel photobioreactor","authors":"Heiko Wagner,&nbsp;Antonia Schad,&nbsp;Sonja Höhmann,&nbsp;Tim Arik Briol,&nbsp;Christian Wilhelm","doi":"10.1186/s13068-024-02479-4","DOIUrl":"10.1186/s13068-024-02479-4","url":null,"abstract":"<div><p>Glycolate is produced by microalgae under photorespiratory conditions and has the potential for sustainable organic carbon production in biotechnology. This study explores the glycolate production balance in <i>Chlamydomonas reinhardtii</i>, using a custom-built 10-L flat panel bioreactor with sophisticated measurements of process factors such as nutrient supply, gassing, light absorption and mass balances. As a result, detailed information regarding carbon and energy balance is obtained to support techno-economic analyses. It is shown how nitrogen is a crucial element in the biotechnological process and monitoring nitrogen content is vital for optimum performance. Moreover, the suitable reactor design is advantageous to efficiently adjust the gas composition. The oxygen content has to be slightly above 30% to induce photorespiration while maintaining photosynthetic efficiency. The final volume productivity reached 27.7 mg of glycolate per litre per hour, thus, the total process capacity can be calculated to 13 tonnes of glycolate per hectare per annum. The exceptional volume productivity of both biomass and glycolate production is demonstrated, and consequently can achieve a yearly CO₂ sequestration rate of 35 tonnes per hectare. Although the system shows such high productivity, there are still opportunities to enhance the achieved volume productivity and thus exploit the biotechnological potential of glycolate production from microalgae.</p></div>","PeriodicalId":494,"journal":{"name":"Biotechnology for Biofuels","volume":"17 1","pages":""},"PeriodicalIF":6.3,"publicationDate":"2024-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://biotechnologyforbiofuels.biomedcentral.com/counter/pdf/10.1186/s13068-024-02479-4","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140133494","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":"Photoautotrophic cultivation of a Chlamydomonas reinhardtii mutant with zeaxanthin as the sole xanthophyll","authors":"Minjae Kim,&nbsp;Stefano Cazzaniga,&nbsp;Junhwan Jang,&nbsp;Matteo Pivato,&nbsp;Gueeda Kim,&nbsp;Matteo Ballottari,&nbsp;EonSeon Jin","doi":"10.1186/s13068-024-02483-8","DOIUrl":"10.1186/s13068-024-02483-8","url":null,"abstract":"<div><h3>Background</h3><p>Photosynthetic microalgae are known for their sustainable and eco-friendly potential to convert carbon dioxide into valuable products. Nevertheless, the challenge of self-shading due to high cell density has been identified as a drawback, hampering productivity in sustainable photoautotrophic mass cultivation. To address this issue, mutants with altered pigment composition have been proposed to allow a more efficient light diffusion but further study on the role of the different pigments is still needed to correctly engineer this process.</p><h3>Results</h3><p>We here investigated the <i>Chlamydomonas reinhardtii Δzl</i> mutant with zeaxanthin as the sole xanthophyll. The <i>Δzl</i> mutant displayed altered pigment composition, characterized by lower chlorophyll content, higher chlorophyll a/b ratio, and lower chlorophyll/carotenoid ratio compared to the wild type (Wt). The <i>Δzl</i> mutant also exhibited a significant decrease in the light-harvesting complex II/Photosystem II ratio (LHCII/PSII) and the absence of trimeric LHCIIs. This significantly affects the organization and stability of PSII supercomplexes. Consequently, the estimated functional antenna size of PSII in the <i>Δzl</i> mutant was approximately 60% smaller compared to that of Wt, and reduced PSII activity was evident in this mutant. Notably, the <i>Δzl</i> mutant showed impaired non-photochemical quenching. However, the <i>Δzl</i> mutant compensated by exhibiting enhanced cyclic electron flow compared to Wt, seemingly offsetting the impaired PSII functionality. Consequently, the <i>Δzl</i> mutant achieved significantly higher cell densities than Wt under high-light conditions.</p><h3>Conclusions</h3><p>Our findings highlight significant changes in pigment content and pigment–protein complexes in the <i>Δzl</i> mutant compared to Wt, resulting in an advantage for high-density photoautotrophic cultivation. This advantage is attributed to the decreased chlorophyll content of the <i>Δzl</i> mutant, allowing better light penetration. In addition, the accumulated zeaxanthin in the mutant could serve as an antioxidant, offering protection against reactive oxygen species generated by chlorophylls.</p></div>","PeriodicalId":494,"journal":{"name":"Biotechnology for Biofuels","volume":"17 1","pages":""},"PeriodicalIF":6.3,"publicationDate":"2024-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://biotechnologyforbiofuels.biomedcentral.com/counter/pdf/10.1186/s13068-024-02483-8","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140133495","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 sustainable bioprocess to produce bacterial cellulose (BC) using waste streams from wine distilleries and the biodiesel industry: evaluation of BC for adsorption of phenolic compounds, dyes and metals","authors":"Erminta Tsouko,&nbsp;Sotirios Pilafidis,&nbsp;Konstantina Kourmentza,&nbsp;Helena I. Gomes,&nbsp;Giannis Sarris,&nbsp;Panagiota Koralli,&nbsp;Aristeidis Papagiannopoulos,&nbsp;Stergios Pispas,&nbsp;Dimitris Sarris","doi":"10.1186/s13068-024-02488-3","DOIUrl":"10.1186/s13068-024-02488-3","url":null,"abstract":"<div><h3>Background</h3><p>The main challenge for large-scale production of bacterial cellulose (BC) includes high production costs interlinked with raw materials, and low production rates. The valorization of renewable nutrient sources could improve the economic effectiveness of BC fermentation while their direct bioconversion into sustainable biopolymers addresses environmental pollution and/or resource depletion challenges. Herein a green bioprocess was developed to produce BC in high amounts with the rather unexplored bacterial strain <i>Komagataeibacter rhaeticus,</i> using waste streams such as wine distillery effluents (WDE) and biodiesel-derived glycerol. Also, BC was evaluated as a bio-adsorbent for phenolics, dyes and metals removal to enlarge its market diversification.</p><h3>Results</h3><p>BC production was significantly affected by the WDE mixing ratio (0–100%), glycerol concentration (20–45 g/L), type of glycerol and media-sterilization method. A maximum BC concentration of 9.0 g/L, with a productivity of 0.90 g/L/day and a water holding capacity of 60.1 g water/g dry BC, was achieved at 100% WDE and ≈30 g/L crude glycerol. BC samples showed typical cellulose vibration bands and average fiber diameters between 37.2 and 89.6 nm. The BC capacity to dephenolize WDE and adsorb phenolics during fermentation reached respectively, up to 50.7% and 26.96 mg gallic acid equivalents/g dry BC (<i>in-situ</i> process). The produced BC was also investigated for dye and metal removal. The highest removal of dye acid yellow 17 (54.3%) was recorded when 5% of BC was applied as the bio-adsorbent. Experiments performed in a multi-metal synthetic wastewater showed that BC could remove up to 96% of Zn and 97% of Cd.</p><h3>Conclusions</h3><p>This work demonstrated a low-carbon approach to produce low-cost, green and biodegradable BC-based bio-adsorbents, without any chemical modification. Their potential in wastewater-treatment-applications was highlighted, promoting closed-loop systems within the circular economy era. This study may serve as an orientation for future research towards competitive or targeted adsorption technologies for wastewater treatment or resources recovery.</p></div>","PeriodicalId":494,"journal":{"name":"Biotechnology for Biofuels","volume":"17 1","pages":""},"PeriodicalIF":6.3,"publicationDate":"2024-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://biotechnologyforbiofuels.biomedcentral.com/counter/pdf/10.1186/s13068-024-02488-3","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140112434","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":"Enhancing enzymatic saccharification yields of cellulose at high solid loadings by combining different LPMO activities","authors":"Camilla F. Angeltveit,&nbsp;Anikó Várnai,&nbsp;Vincent G. H. Eijsink,&nbsp;Svein J. Horn","doi":"10.1186/s13068-024-02485-6","DOIUrl":"10.1186/s13068-024-02485-6","url":null,"abstract":"<div><h3>Background</h3><p>The 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.</p><h3>Results</h3><p>An LPMO-poor cellulase cocktail, Celluclast 1.5 L, was spiked with one or both of two fungal LPMOs from <i>Thermothielavioides terrestris</i> and <i>Thermoascus aurantiacus, Tt</i>AA9E and <i>Ta</i>AA9A, 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).</p><h3>Conclusions</h3><p>This 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.</p></div>","PeriodicalId":494,"journal":{"name":"Biotechnology for Biofuels","volume":"17 1","pages":""},"PeriodicalIF":6.3,"publicationDate":"2024-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://biotechnologyforbiofuels.biomedcentral.com/counter/pdf/10.1186/s13068-024-02485-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140069012","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":"EnZolv delignification of cotton spinning mill waste and optimization of process parameters using response surface methodology (RSM)","authors":"Santhoshkumar Subramaniam,&nbsp;Kumutha Karunanandham,&nbsp;A. S. M. Raja,&nbsp;S. K. Shukla,&nbsp;Sivakumar Uthandi","doi":"10.1186/s13068-024-02473-w","DOIUrl":"10.1186/s13068-024-02473-w","url":null,"abstract":"<div><h3>Background</h3><p>EnZolv is a novel enzyme-based, eco-friendly biomass pretreatment process that has shown great potential in the field of textile engineering and biotechnology. It employs laccase from <i>Hexagonia hirta</i> MSF2 and 2% ethanol in the process of delignification. The process is designed to evaluate optimal conditions to remove lignin and other impurities from cotton spinning mill waste (CSMW), without compromising the quality and strength of the fibers. CSMW is a low-cost and readily available source of cellulose, making it an ideal candidate for delignification using EnZolv. By optimizing the pretreatment conditions and harnessing the potential of enzymatic delignification, this research aims to contribute to more sustainable and efficient ways of utilizing lignocellulosic biomass in various industries for the production of biochemical and bioproducts.</p><h3>Results</h3><p>The present study emphasizes the EnZolv pretreatment in the delignification of cotton spinning mill wastes irrespective of the cellulose content. EnZolv process parameters such as, moisture content, enzyme load, incubation time, incubation temperature, and shaking speed were optimized. Under pre-optimized conditions, the percent lignin reduction was 61.34%, 61.64%, 41.85%, 35.34%, and 35.83% in blowroom droppings (BD), flat strips (FS), lickerin fly (LF), microdust (MD) and comber noils (CN), respectively. Using response surface methodology (RSM), the statistically optimized EnZolv pretreatment conditions showed lignin reduction of 59.16%, 62.88%, 48.26%, 34.64%, and 45.99% in BD, FS, LF, MD, and CN, respectively.</p><h3>Conclusion</h3><p>Traditional chemical-based pretreatment methods often involve harsh chemicals and high energy consumption, which can have detrimental effects on the environment. In contrast, EnZolv offers a greener approach by utilizing enzymes that are biodegradable and more environmentally friendly. The resulting fibers from EnZolv treatment exhibit improved properties that make them suitable for various applications. Some of the key properties include enhanced cellulose recovery, reduced lignin content, and improved biophysical and structural characteristics. These improvements can contribute to the fiber's performance and processability in different industries and future thrust for the production of cellulose-derived and lignin-derived bioproducts.</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":6.3,"publicationDate":"2024-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://biotechnologyforbiofuels.biomedcentral.com/counter/pdf/10.1186/s13068-024-02473-w","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140051285","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":"Kinetics-based development of two-stage continuous fermentation of 1,3-propanediol from crude glycerol by Clostridium butyricum","authors":"Xiao-Li Wang,&nbsp;Ya-Qin Sun,&nbsp;Duo-Tao Pan,&nbsp;Zhi-Long Xiu","doi":"10.1186/s13068-024-02486-5","DOIUrl":"10.1186/s13068-024-02486-5","url":null,"abstract":"<div><h3>Background</h3><p>Glycerol, 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.</p><h3>Results</h3><p>In this study, a three-stage continuous fermentation was firstly designed to produce 1,3-PDO from crude glycerol by <i>Clostridium butyricum</i>, 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.</p><h3>Conclusion</h3><p>A 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.</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":6.3,"publicationDate":"2024-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://biotechnologyforbiofuels.biomedcentral.com/counter/pdf/10.1186/s13068-024-02486-5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140061544","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}