Biotechnology for Biofuels最新文献

{"title":"Enhancing the production of PHA in Scenedesmus sp. by the addition of green synthesized nitrogen, phosphorus, and nitrogen–phosphorus-doped carbon dots","authors":"Pablo Alfredo Sánchez-Pineda,&nbsp;Itzel Y. López-Pacheco,&nbsp;Angel M. Villalba-Rodríguez,&nbsp;José Alfonso Godínez-Alemán,&nbsp;Reyna Berenice González-González,&nbsp;Roberto Parra-Saldívar,&nbsp;Hafiz M. N. Iqbal","doi":"10.1186/s13068-024-02522-4","DOIUrl":"10.1186/s13068-024-02522-4","url":null,"abstract":"<div><p>Plastic consumption has increased globally, and environmental issues associated with it have only gotten more severe; as a result, the search for environmentally friendly alternatives has intensified. Polyhydroxyalkanoates (PHA), as biopolymers produced by microalgae, might be an excellent option; however, large-scale production is a relevant barrier that hinders their application. Recently, innovative materials such as carbon dots (CDs) have been explored to enhance PHA production sustainably. This study added green synthesized multi-doped CDs to <i>Scenedesmus</i> sp. microalgae cultures to improve PHA production. Prickly pear was selected as the carbon precursor for the hydrothermally synthesized CDs doped with nitrogen, phosphorous, and nitrogen–phosphorous elements. CDs were characterized by different techniques, such as FTIR, SEM, ζ potential, UV–Vis, and XRD. They exhibited a semi-crystalline structure with high concentrations of carboxylic groups on their surface and other elements, such as copper and phosphorus. A medium without nitrogen and phosphorous was used as a control to compare CDs-enriched mediums. Cultures regarding biomass growth, carbohydrates, lipids, proteins, and PHA content were analyzed. The obtained results demonstrated that CDs-enriched cultures produced higher content of biomass and PHA; CDs-enriched cultures presented an increase of 26.9% in PHA concentration and an increase of 32% in terms of cell growth compared to the standard cultures.</p></div>","PeriodicalId":494,"journal":{"name":"Biotechnology for Biofuels","volume":"17 1","pages":""},"PeriodicalIF":6.3,"publicationDate":"2024-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://biotechnologyforbiofuels.biomedcentral.com/counter/pdf/10.1186/s13068-024-02522-4","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141245322","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 anaerobic digestion of lignocellulosic biomass by mechanical cotreatment","authors":"Anahita Bharadwaj,&nbsp;Evert K. Holwerda,&nbsp;John M. Regan,&nbsp;Lee R. Lynd,&nbsp;Tom L. Richard","doi":"10.1186/s13068-024-02521-5","DOIUrl":"10.1186/s13068-024-02521-5","url":null,"abstract":"<div><h3>Background</h3><p>The aim of this study was to increase the accessibility and accelerate the breakdown of lignocellulosic biomass to methane in an anaerobic fermentation system by mechanical <i>cotreatment</i>: milling during fermentation, as an alternative to conventional <i>pre</i>treatment prior to biological deconstruction. Effluent from a mesophilic anaerobic digester running with unpretreated senescent switchgrass as the predominant carbon source was collected and subjected to ball milling for 0.5, 2, 5 and 10 min. Following this, a batch fermentation test was conducted with this material in triplicate for an additional 18 days with unmilled effluent as the ‘status quo’ control.</p><h3>Results</h3><p>The results indicate 0.5 – 10 min of cotreatment increased sugar solubilization by 5– 13% when compared to the unmilled control, with greater solubilization correlated with increased milling duration. Biogas concentrations ranged from 44% to 55.5% methane with the balance carbon dioxide. The total biogas production was statistically higher than the unmilled control for all treatments with 2 or more minutes of milling (α = 0.1). Cotreatment also decreased mean particle size. Energy consumption measurements of a lab-scale mill indicate that longer durations of milling offer diminishing benefits with respect to additional methane production.</p><h3>Conclusions</h3><p>Cotreatment in anaerobic digestion systems, as demonstrated in this study, provides an alternative approach to conventional pretreatments to increase biogas production from lignocellulosic grassy material.</p></div>","PeriodicalId":494,"journal":{"name":"Biotechnology for Biofuels","volume":"17 1","pages":""},"PeriodicalIF":6.3,"publicationDate":"2024-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://biotechnologyforbiofuels.biomedcentral.com/counter/pdf/10.1186/s13068-024-02521-5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141237413","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":"Selectively superior production of docosahexaenoic acid in Schizochytrium sp. through engineering the fatty acid biosynthetic pathways","authors":"Yana Liu,&nbsp;Xiao Han,&nbsp;Zongcheng Chen,&nbsp;Yihan Yan,&nbsp;Zhi Chen","doi":"10.1186/s13068-024-02524-2","DOIUrl":"10.1186/s13068-024-02524-2","url":null,"abstract":"<div><h3>Background</h3><p><i>Schizochytrium</i> sp. is commercially used for production of docosahexaenoic acid (DHA). <i>Schizochytrium</i> sp. utilizes the polyketide synthase complex (PKS) and a single type I fatty acid synthase (FAS) to synthesize polyunsaturated fatty acids and saturated fatty acids, respectively. The acyl carrier protein (ACP) domains of FAS or PKS are used to load acyl groups during fatty acids biosynthesis. Phosphopantetheinyl transferase (PPTase) transfers the pantetheine moiety from Coenzyme A to the conserved serine residue of an inactive ACP domain to produce its active form.</p><h3>Results</h3><p>In this study, in order to improve production and content of DHA, we decreased the expression of <i>fas</i>, strengthened the expression of the PKS pathway, and enhanced the supply of active ACP in <i>Schizochytrium</i> sp. ATCC20888. Weakening the expression of <i>fas</i> or disruption of <i>orfA</i> both led to growth defect and reduction of lipid yields in the resulting strains WFAS and DPKSA, indicating that both FAS and PKS were indispensable for growth and lipid accumulation. Although WFAS had a higher DHA content in total fatty acids than the wild-type strain (WT), its growth defect and low DHA yield hinders its use for DHA production. Overexpression of the <i>orfAB</i>, <i>orfC</i>, <i>orfC</i>-<i>DH</i> (truncated <i>orfC</i>), or <i>ppt</i> promoted DHA and lipid production, respectively. The yields and contents of DHA were further increased by combined overexpression of these genes. Highest values of DHA yield (7.2 g/L) and DHA content (40.6%) were achieved in a recombinant OPKSABC-PPT, ⁓56.5% and 15.3% higher than the WT values, respectively.</p><h3>Conclusions</h3><p>This study demonstrates that genetic engineering of the fatty acid biosynthetic pathways provides a new strategy to enhance DHA production in <i>Schizochytrium</i>.</p></div>","PeriodicalId":494,"journal":{"name":"Biotechnology for Biofuels","volume":"17 1","pages":""},"PeriodicalIF":6.3,"publicationDate":"2024-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://biotechnologyforbiofuels.biomedcentral.com/counter/pdf/10.1186/s13068-024-02524-2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141237646","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":"Structure–function characterization of two enzymes from novel subfamilies of manganese peroxidases secreted by the lignocellulose-degrading Agaricales fungi Agrocybe pediades and Cyathus striatus","authors":"María Isabel Sánchez-Ruiz,&nbsp;Elena Santillana,&nbsp;Dolores Linde,&nbsp;Antonio Romero,&nbsp;Angel T. Martínez,&nbsp;Francisco Javier Ruiz-Dueñas","doi":"10.1186/s13068-024-02517-1","DOIUrl":"10.1186/s13068-024-02517-1","url":null,"abstract":"<div><h3>Background</h3><p>Manganese peroxidases (MnPs) are, together with lignin peroxidases and versatile peroxidases, key elements of the enzymatic machineries secreted by white-rot fungi to degrade lignin, thus providing access to cellulose and hemicellulose in plant cell walls. A recent genomic analysis of 52 Agaricomycetes species revealed the existence of novel MnP subfamilies differing in the amino-acid residues that constitute the manganese oxidation site. Following this in silico analysis, a comprehensive structure–function study is needed to understand how these enzymes work and contribute to transform the lignin macromolecule.</p><h3>Results</h3><p>Two MnPs belonging to the subfamilies recently classified as MnP-DGD and MnP-ESD—referred to as Ape-MnP1 and Cst-MnP1, respectively—were identified as the primary peroxidases secreted by the Agaricales species <i>Agrocybe pediades</i> and <i>Cyathus striatus</i> when growing on lignocellulosic substrates. Following heterologous expression and in vitro activation, their biochemical characterization confirmed that these enzymes are active MnPs. However, crystal structure and mutagenesis studies revealed manganese coordination spheres different from those expected after their initial classification. Specifically, a glutamine residue (Gln333) in the C-terminal tail of Ape-MnP1 was found to be involved in manganese binding, along with Asp35 and Asp177, while Cst-MnP1 counts only two amino acids (Glu36 and Asp176), instead of three, to function as a MnP. These findings led to the renaming of these subfamilies as MnP-DDQ and MnP-ED and to re-evaluate their evolutionary origin. Both enzymes were also able to directly oxidize lignin-derived phenolic compounds, as seen for other short MnPs. Importantly, size-exclusion chromatography analyses showed that both enzymes cause changes in polymeric lignin in the presence of manganese, suggesting their relevance in lignocellulose transformation.</p><h3>Conclusions</h3><p>Understanding the mechanisms used by basidiomycetes to degrade lignin is of particular relevance to comprehend carbon cycle in nature and to design biotechnological tools for the industrial use of plant biomass. Here, we provide the first structure–function characterization of two novel MnP subfamilies present in Agaricales mushrooms, elucidating the main residues involved in catalysis and demonstrating their ability to modify the lignin macromolecule.</p></div>","PeriodicalId":494,"journal":{"name":"Biotechnology for Biofuels","volume":"17 1","pages":""},"PeriodicalIF":6.3,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://biotechnologyforbiofuels.biomedcentral.com/counter/pdf/10.1186/s13068-024-02517-1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141187274","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":"Modifying lignin composition and xylan O-acetylation induces changes in cell wall composition, extractability, and digestibility","authors":"Aniket Anant Chaudhari,&nbsp;Anant Mohan Sharma,&nbsp;Lavi Rastogi,&nbsp;Bhagwat Prasad Dewangan,&nbsp;Raunak Sharma,&nbsp;Deepika Singh,&nbsp;Rajan Kumar Sah,&nbsp;Shouvik Das,&nbsp;Saikat Bhattacharjee,&nbsp;Ewa J. Mellerowicz,&nbsp;Prashant Anupama-Mohan Pawar","doi":"10.1186/s13068-024-02513-5","DOIUrl":"10.1186/s13068-024-02513-5","url":null,"abstract":"<div><h3>Background</h3><p>Lignin and xylan are important determinants of cell wall structure and lignocellulosic biomass digestibility. Genetic manipulations that individually modify either lignin or xylan structure improve polysaccharide digestibility. However, the effects of their simultaneous modifications have not been explored in a similar context. Here, both individual and combinatorial modification in xylan and lignin was studied by analysing the effect on plant cell wall properties, biotic stress responses and integrity sensing.</p><h3>Results</h3><p>Arabidopsis plant co-harbouring mutation in FERULATE 5-HYDROXYLASE (<i>F5H</i>) and overexpressing <i>Aspergillus niger</i> acetyl xylan esterase (35S:<i>An</i>AXE1) were generated and displayed normal growth attributes with intact xylem architecture. This <i>fah1-2</i>/35S:<i>An</i>AXE1 cross was named as <b>h</b>ype<b>r G</b> lignin and <b>hyp</b>o<b>ac</b>etylated (HrGHypAc) line. The HrGHypAc plants showed increased crystalline cellulose content with enhanced digestibility after chemical and enzymatic pre-treatment. Moreover, both parents and HrGHypAc without and after pre-treating with glucuronyl esterase and alpha glucuronidase exhibited an increase in xylose release after xylanase digestion as compared to wild type. The de-pectinated fraction in HrGHypAc displayed elevated levels of xylan and cellulose. Furthermore, the transcriptomic analysis revealed differential expression in cell wall biosynthetic, transcription factors and wall-associated kinases genes implying the role of lignin and xylan modification on cellular regulatory processes.</p><h3>Conclusions</h3><p>Simultaneous modification in xylan and lignin enhances cellulose content with improved saccharification efficiency. These modifications loosen cell wall complexity and hence resulted in enhanced xylose and xylobiose release with or without pretreatment after xylanase digestion in both parent and HrGHypAc. This study also revealed that the disruption of xylan and lignin structure is possible without compromising either growth and development or defense responses against <i>Pseudomonas syringae</i> infection.</p></div>","PeriodicalId":494,"journal":{"name":"Biotechnology for Biofuels","volume":"17 1","pages":""},"PeriodicalIF":6.3,"publicationDate":"2024-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://biotechnologyforbiofuels.biomedcentral.com/counter/pdf/10.1186/s13068-024-02513-5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141187273","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":"Recent advances in bio-based production of top platform chemical, succinic acid: an alternative to conventional chemistry","authors":"Vinod Kumar,&nbsp;Pankaj Kumar,&nbsp;Sunil K. Maity,&nbsp;Deepti Agrawal,&nbsp;Vivek Narisetty,&nbsp;Samuel Jacob,&nbsp;Gopalakrishnan Kumar,&nbsp;Shashi Kant Bhatia,&nbsp;Dinesh Kumar,&nbsp;Vivekanand Vivekanand","doi":"10.1186/s13068-024-02508-2","DOIUrl":"10.1186/s13068-024-02508-2","url":null,"abstract":"<div><p>Succinic acid (SA) is one of the top platform chemicals with huge applications in diverse sectors. The presence of two carboxylic acid groups on the terminal carbon atoms makes SA a highly functional molecule that can be derivatized into a wide range of products. The biological route for SA production is a cleaner, greener, and promising technological option with huge potential to sequester the potent greenhouse gas, carbon dioxide. The recycling of renewable carbon of biomass (an indirect form of CO₂), along with fixing CO₂ in the form of SA, offers a carbon-negative SA manufacturing route to reduce atmospheric CO₂ load. These attractive attributes compel a paradigm shift from fossil-based to microbial SA manufacturing, as evidenced by several commercial-scale bio-SA production in the last decade. The current review article scrutinizes the existing knowledge and covers SA production by the most efficient SA producers, including several bacteria and yeast strains. The review starts with the biochemistry of the major pathways accumulating SA as an end product. It discusses the SA production from a variety of pure and crude renewable sources by native as well as engineered strains with details of pathway/metabolic, evolutionary, and process engineering approaches for enhancing TYP (titer, yield, and productivity) metrics. The review is then extended to recent progress on separation technologies to recover SA from fermentation broth. Thereafter, SA derivatization opportunities via chemo-catalysis are discussed for various high-value products, which are only a few steps away. The last two sections are devoted to the current scenario of industrial production of bio-SA and associated challenges, along with the author's perspective.</p></div>","PeriodicalId":494,"journal":{"name":"Biotechnology for Biofuels","volume":"17 1","pages":""},"PeriodicalIF":6.3,"publicationDate":"2024-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://biotechnologyforbiofuels.biomedcentral.com/counter/pdf/10.1186/s13068-024-02508-2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141173743","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":"Reconstruction of a genome-scale metabolic model and in-silico flux analysis of Aspergillus tubingensis: a non-mycotoxinogenic citric acid-producing fungus","authors":"Mehak Kaushal,&nbsp;Daniel J. Upton,&nbsp;Jai K. Gupta,&nbsp;A. Jamie Wood,&nbsp;Shireesh Srivastava","doi":"10.1186/s13068-024-02506-4","DOIUrl":"10.1186/s13068-024-02506-4","url":null,"abstract":"<div><h3>Background</h3><p><i>Aspergillus tubingensis</i> is a citric acid-producing fungus that can utilize sugars in hydrolysate of lignocellulosic biomass such as sugarcane bagasse and, unlike <i>A. niger</i>, does not produce mycotoxins. To date, no attempt has been made to model its metabolism at genome scale.</p><h3>Results</h3><p>Here, we utilized the whole-genome sequence (34.96 Mb length) and the measured biomass composition to reconstruct a genome-scale metabolic model (GSMM) of <i>A. tubingensis</i> DJU120 strain. The model, named <i>i</i>MK1652, consists of 1652 genes, 1657 metabolites and 2039 reactions distributed over four cellular compartments. The model has been extensively curated manually. This included removal of dead-end metabolites and generic reactions, addition of secondary metabolite pathways and several transporters. Several mycotoxin synthesis pathways were either absent or incomplete in the genome, providing a genomic basis for the non-toxinogenic nature of this species. The model was further refined based on the experimental phenotypic microarray (Biolog) data. The model closely captured DJU120 fermentative data on glucose, xylose, and phosphate consumption, as well as citric acid and biomass production, showing its applicability to capture citric acid fermentation of lignocellulosic biomass hydrolysate.</p><h3>Conclusions</h3><p>The model offers a framework to conduct metabolic systems biology investigations and can act as a scaffold for integrative modelling of <i>A. tubingensis</i>.</p></div>","PeriodicalId":494,"journal":{"name":"Biotechnology for Biofuels","volume":"17 1","pages":""},"PeriodicalIF":6.3,"publicationDate":"2024-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://biotechnologyforbiofuels.biomedcentral.com/counter/pdf/10.1186/s13068-024-02506-4","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141162826","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":"Cell envelope and stress-responsive pathways underlie an evolved oleaginous Rhodotorula toruloides strain multi-stress tolerance","authors":"Miguel Antunes,&nbsp;Marta N. Mota,&nbsp;Isabel Sá-Correia","doi":"10.1186/s13068-024-02518-0","DOIUrl":"10.1186/s13068-024-02518-0","url":null,"abstract":"<div><h3>Background</h3><p>The red oleaginous yeast <i>Rhodotorula toruloides</i> is a promising cell factory to produce microbial oils and carotenoids from lignocellulosic hydrolysates (LCH). A multi-stress tolerant strain towards four major inhibitory compounds present in LCH and methanol, was derived in our laboratory from strain IST536 (PYCC 5615) through adaptive laboratory evolution (ALE) under methanol and high glycerol selective pressure.</p><h3>Results</h3><p>Comparative genomic analysis suggested the reduction of the original strain ploidy from triploid to diploid, the occurrence of 21,489 mutations, and 242 genes displaying copy number variants in the evolved strain. Transcriptomic analysis identified 634 genes with altered transcript levels (465 up, 178 down) in the multi-stress tolerant strain. Genes associated with cell surface biogenesis, integrity, and remodelling and involved in stress-responsive pathways exhibit the most substantial alterations at the genome and transcriptome levels. Guided by the suggested stress responses, the multi-stress tolerance phenotype was extended to osmotic, salt, ethanol, oxidative, genotoxic, and medium-chain fatty acid-induced stresses.</p><h3>Conclusions</h3><p>The comprehensive analysis of this evolved strain provided the opportunity to get mechanistic insights into the acquisition of multi-stress tolerance and a list of promising genes, pathways, and regulatory networks, as targets for synthetic biology approaches applied to promising cell factories, toward more robust and superior industrial strains. This study lays the foundations for understanding the mechanisms underlying tolerance to multiple stresses in <i>R. toruloides</i>, underscoring the potential of ALE for enhancing the robustness of industrial yeast strains.</p></div>","PeriodicalId":494,"journal":{"name":"Biotechnology for Biofuels","volume":"17 1","pages":""},"PeriodicalIF":6.3,"publicationDate":"2024-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://biotechnologyforbiofuels.biomedcentral.com/counter/pdf/10.1186/s13068-024-02518-0","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141162824","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":"Effect of addition of γ-poly glutamic acid on bacterial nanocellulose production under agitated culture conditions","authors":"Yang Bai,&nbsp;Ran Tan,&nbsp;Yiran Yan,&nbsp;Tao Chen,&nbsp;Yetong Feng,&nbsp;Qiwei Sun,&nbsp;Jiakun Li,&nbsp;Yifei Wang,&nbsp;Futao Liu,&nbsp;Jingwen Wang,&nbsp;Yao Zhang,&nbsp;Xianhao Cheng,&nbsp;Guochao Wu","doi":"10.1186/s13068-024-02515-3","DOIUrl":"10.1186/s13068-024-02515-3","url":null,"abstract":"<div><h3>Background</h3><p>Bacterial nanocellulose (BNC), a natural polymer material, gained significant popularity among researchers and industry. It has great potential in areas, such as textile manufacturing, fiber-based paper, and packaging products, food industry, biomedical materials, and advanced functional bionanocomposites. The main current fermentation methods for BNC involved static culture, as the agitated culture methods had lower raw material conversion rates and resulted in non-uniform product formation. Currently, studies have shown that the production of BNC can be enhanced by incorporating specific additives into the culture medium. These additives included organic acids or polysaccharides. γ-Polyglutamic acid (γ-PGA), known for its high polymerization, excellent biodegradability, and environmental friendliness, has found extensive application in various industries including daily chemicals, medicine, food, and agriculture.</p><h3>Results</h3><p>In this particular study, 0.15 g/L of γ-PGA was incorporated as a medium additive to cultivate BNC under agitated culture conditions of 120 rpm and 30 ℃. The BNC production increased remarkably by 209% in the medium with 0.15 g/L γ-PGA and initial pH of 5.0 compared to that in the standard medium, and BNC production increased by 7.3% in the medium with 0.06 g/L γ-PGA. The addition of γ-PGA as a medium additive resulted in significant improvements in BNC production. Similarly, at initial pH levels of 4.0 and 6.0, the BNC production also increased by 39.3% and 102.3%, respectively. To assess the characteristics of the BNC products, scanning electron microscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis were used. The average diameter of BNC fibers, which was prepared from the medium adding 0.15 g/L γ-PGA, was twic<u>e</u> thicker than that of BNC fibers prepared from the control culture medium. That might be because that polyglutamic acid relieved the BNC synthesis from the shear stress from the agitation.</p><h3>Conclusions</h3><p>This experiment held great significance as it explored the use of a novel medium additive, γ-PGA, to improve the production and the glucose conversion rate in BNC fermentation. And the BNC fibers became thicker, with better thermal stability, higher crystallinity, and higher degree of polymerization (DPv). These findings lay a solid foundation for future large-scale fermentation production of BNC using bioreactors.</p></div>","PeriodicalId":494,"journal":{"name":"Biotechnology for Biofuels","volume":"17 1","pages":""},"PeriodicalIF":6.3,"publicationDate":"2024-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://biotechnologyforbiofuels.biomedcentral.com/counter/pdf/10.1186/s13068-024-02515-3","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141156454","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":"Blocking miR396 activity by overexpression MIM396 improved switchgrass tiller number and biomass yield","authors":"Mingzhi Xu,&nbsp;Lin Li,&nbsp;Jianping Yan,&nbsp;Dayong Li,&nbsp;Yaling Liu,&nbsp;Wanjun Zhang,&nbsp;Yanrong Liu","doi":"10.1186/s13068-024-02514-4","DOIUrl":"10.1186/s13068-024-02514-4","url":null,"abstract":"<div><h3>Background</h3><p>MicroRNA396 (miR396) plays an important role in the regulation of plant growth and development by repressing the expression level of its target growth-regulating factor (GRF) family genes. In our previous study, we found that overexpression of miR396 negatively regulated both tillering and biomass yield in switchgrass (<i>Panicum virgatum</i> L.). We, therefore, speculated that blocking the expression of miR396 could enhance switchgrass tillering and biomass yield. Here, we produced transgenic switchgrass plants overexpressing a target mimicry form of miR396 (<i>MIM396</i>) in wild type (WT) and <i>Os-MIR319b</i> overexpressing switchgrass plant (with higher enzymatic hydrolysis efficiency, but reduced tillering), in which the expression of miR396 was blocked. The phenotype and biological yields of these plants were analyzed.</p><h3>Results</h3><p>Blocking miR396 to improve its target <i>PvGRFs</i> expression in switchgrass improved the tiller number and dry weight of transgenic plants. Further morphological analysis revealed that <i>MIM396</i> plants increased the number of aerial branches and basal tillers compared to those of wild-type plants. The enzymatic efficiency of <i>MIM396</i> plants was reduced; however, the total sugar production per plant was still significantly higher than that of wild-type plants due to the increase in biomass. In addition, blocking miR396 in a transgenic switchgrass plant overexpressing <i>Os-MIR319b</i> (TG21-Ms) significantly increased the <i>PvGRF1/3/5</i> expression level and tiller number and biomass yield. The miR156-target gene <i>PvSPL4</i>, playing a negative role in aerial and basal buds outgrowth, showed significant downregulated in <i>MIM396</i> and TG21-Ms. Those results indicate that miR396-<i>PvGRFs</i>, through disrupting the <i>PvSPL4</i> expression, are involved in miR319-<i>PvPCFs</i> in regulating tiller number, at least partly.</p><h3>Conclusions</h3><p><i>MIM396</i> could be used as a molecular tool to improving tiller number and biomass yield in switchgrass wild type and miR319b transgenic plants. This finding may be applied to other graminaceous plants to regulate plant biological yield.</p></div>","PeriodicalId":494,"journal":{"name":"Biotechnology for Biofuels","volume":"17 1","pages":""},"PeriodicalIF":6.3,"publicationDate":"2024-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://biotechnologyforbiofuels.biomedcentral.com/counter/pdf/10.1186/s13068-024-02514-4","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141158743","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}