Biotechnology for Biofuels最新文献

{"title":"Lutein biosynthesis and pigment dynamics in a partially chlorophyll-deficient mutant of Chlorella sp. under autotrophic, mixotrophic, and heterotrophic cultivation","authors":"Manlin Yan,&nbsp;Ting Liu,&nbsp;Xupeng Cao,&nbsp;Quanyu Zhao","doi":"10.1186/s13068-026-02785-z","DOIUrl":"10.1186/s13068-026-02785-z","url":null,"abstract":"<div><h3>Background</h3><p>The color of microalgae is related to the components and contents of pigments. Yellow microalgae have a low chlorophyll content, which is helpful for obtaining high-purity lutein during downstream extraction. Chlorophyll and lutein content changes under different culture modes if chlorophyll biosynthesis is not fully destroyed. Low chlorophyll content improved the purity of the final lutein product. It is not fully known about the lutein biosynthesis and pigment dynamics in yellow microalgae under different culture modes.</p><h3>Results</h3><p>A yellow algal mutant <i>Chlorella</i> sp. M04 strain was obtained via chemical mutagenesis. The effects of the culture mode (autotrophic, mixotrophic, and heterotrophic) and carbon source were evaluated on the original strain (<i>Chlorella</i> sp. AE10), and the mutant. The ratios of lutein contents to (Chl a + Chl b) contents in the wild type and the mutant were 1:3.5 and 1:0.79, respectively. The highest lutein production observed in the original strain was 3.87 mg/L/d at day 3 under mixotrophic conditions. The lutein productivity of the mutant under heterotrophic conditions was 1.88 mg/L/d on day 2, which was higher than that under autotrophic and mixotrophic conditions. The chlorophyll-a content of the mutant (<i>Chlorella</i> sp. M04) decreased by 88.8% of chlorophyll-a content of the original strain, and chlorophyll b of the mutant was 7.2% of that of the original one under mixotrophic conditions on day 5. Glucose was found to be more suitable than acetic acid for the mutant. Comparative transcriptomic analysis was performed for the original and mutant strains, particularly for the biosynthesis pathways of chlorophyll and lutein.</p><h3>Conclusion</h3><p>The advantage of this mutant is its low chlorophyll content, making it suitable for downstream processes. This study provides new insights into the metabolic regulation of chlorophyll and lutein production in microalgae.</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":"19 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2026-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1186/s13068-026-02785-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148254874","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":"Biosynthesis of medium-chain length polyhydroxyalkanoates from pre-treated food wastewater","authors":"Aghasa Aghasa,&nbsp;Ranaprathap Katakojwala,&nbsp;Eunseok Lee,&nbsp;Sudharshan Juntupally,&nbsp;Hyung-Sool Lee","doi":"10.1186/s13068-026-02780-4","DOIUrl":"10.1186/s13068-026-02780-4","url":null,"abstract":"<div><h3>Background</h3><p>The escalating global plastic waste crisis, coupled with the challenges of managing high-moisture food waste from industrial processing, has prompted nations worldwide to pursue sustainable alternatives and comprehensive waste-reduction strategies. This study addresses this dual challenge by optimizing medium-chain-length polyhydroxyalkanoate (mcl-PHA) production from food wastewater (FWW) using <i>Pseudomonas putida</i> through an iterative refinement process, offering a solution that converts waste into biodegradable plastics.</p><h3>Results</h3><p>In synthetic substrate tests, the highest PHA yield was 0.70 ± 0.05 g PHA/g VSS, with poly(3-hydroxydecanoate) constituting the majority (77.5 ± 2.6%) of the PHA composition, followed by poly(3-hydroxyoctanoate) (15.6 ± 8.8%). These tests underscored the potential of ethanol as a significant contributor to mcl-PHA biosynthesis. In actual substrate tests using pre-treated soluble FWW (P-FWW), the optimal PHA yield was 0.33 ± 0.02 g PHA/g VSS at an F/M ratio of 5. Lower F/M levels (5–25) predominantly produced short-chain-length PHA (scl-PHA), mainly in the form of poly(3-hydroxybutyrate), while higher F/M levels (50–100) favored mcl-PHA, specifically poly(3-hydroxydecanoate).</p><h3>Conclusions</h3><p>This study demonstrates that FWW can be effectively valorized as a sustainable feedstock for PHA production, transforming an industrial waste stream into a valuable biopolymer resource. By establishing the critical relationship between feeding strategy (F/M ratio) and PHA composition, this research provides practical guidelines for optimizing microbial biosynthesis at scale. These findings contribute to circular economy principles by simultaneously addressing food-waste management and reducing dependence on petroleum-based plastics, positioning PHA production from FWW as a viable pathway toward sustainable biomanufacturing.</p></div>","PeriodicalId":494,"journal":{"name":"Biotechnology for Biofuels","volume":"19 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2026-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1186/s13068-026-02780-4.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148213667","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":"Light quality rewires module–trait networks in Euglena gracilis to drive carotenoid and paramylon accumulation","authors":"Ming Du,&nbsp;Zixi Chen,&nbsp;Qingqing Guo,&nbsp;Jing Liu,&nbsp;Ke Xu,&nbsp;Tianming Chen,&nbsp;Chao Li,&nbsp;Yanling Li,&nbsp;Jiangxin Wang","doi":"10.1186/s13068-026-02774-2","DOIUrl":"10.1186/s13068-026-02774-2","url":null,"abstract":"<div><h3>Background</h3><p>Light quality is a critical and tractable parameter for directing carbon partitioning in microalgae toward the synthesis of high-value bioproducts. In this study, <i>Euglena gracilis</i> was employed as a model photosynthetic system to investigate spectral regulation of bioproduct accumulation. An integrative approach combining physiological measurements, quantification of major bioproducts (including chlorophylls, carotenoids, lipids, protein, and the β-1,3-glucan paramylon), and RNA-sequencing-based weighted gene co-expression network analysis (WGCNA) was used to dissect spectrum-specific regulatory programs.</p><h3>Results</h3><p>Distinct spectral treatments induced divergent photochemical responses (<i>Fv</i>/<i>Fm</i>) and bioproduct profiles. WGCNA identified 12 transcriptional modules, which were correlated with specific traits and treatments using module eigengene analysis. One module, enriched in carotenoid biosynthesis genes, showed a strong positive correlation with total carotenoid content (<i>r</i> ≈ 0.85, <i>p</i> &lt; 0.001). A separate module associated with photosystem function and photoprotection closely tracked changes in <i>Fv</i>/<i>Fm</i> (<i>r</i> ≈ 0.75, <i>p</i> ≈ 0.03). Notably, a third module responsive to blue-light-dominant conditions displayed positive correlations with chlorophyll a, carotenoids, and paramylon (|<i>r</i>| ≈ 0.74–0.79; <i>p</i> &lt; 0.05), suggesting an integrated regulatory axis linking light perception, photosynthetic performance, and carbon storage. Additional modules correlated with protein accumulation and broad-spectrum (white) light exposure, implicating coordinated regulation of translational capacity and cytoskeletal dynamics.</p><h3>Conclusions</h3><p>Collectively, these module–trait associations elucidate how light quality orchestrates plastidial function, redox homeostasis, isoprenoid biosynthesis, and <i>β</i>-1,3-glucan metabolism to reprogram bioproduct yields. This network framework identifies candidate pathway regulators and provides strategic insights for optimizing spectral conditions to enhance carotenoid and paramylon production in <i>E. gracilis</i>, supporting advanced microalgal biorefinery development.</p></div>","PeriodicalId":494,"journal":{"name":"Biotechnology for Biofuels","volume":"19 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2026-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1186/s13068-026-02774-2.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148058785","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":"Rational structural design for the dual enhancement of catalytic activity and thermal stability of hyaluronidase from Citrobacter portucalensis","authors":"Yuanying Zhu,&nbsp;Shijunyin Chen,&nbsp;Feiyang Li,&nbsp;Yaya Yao,&nbsp;Yuejia Ji,&nbsp;Wei Feng,&nbsp;Zhongkai Wang,&nbsp;Xuepeng Li,&nbsp;Haitao Yue","doi":"10.1186/s13068-026-02772-4","DOIUrl":"10.1186/s13068-026-02772-4","url":null,"abstract":"<div><p>Hyaluronidases (HAase) offer a practical route to produce valued low molecular weight hyaluronic acid (LMW-HA) and HA oligosaccharides (o-HA), which are valued across medical, cosmetic, and biomaterials applications due to their enhanced bioactivity and tissue penetration. However, reliable production and scale-up of LMW‑HA and o‑HA remain complicated due to inefficient production method, potential pathogenic hosts, enzymes with limited catalytic proficiency and prone to thermal denaturation. Here, we employed a structure-guided multi-strategy engineering approach to express and optimize a PL8 family hyaluronidase in <i>E. coli</i>, aiming to overcome these industrial bottlenecks. Using the HA tetrasaccharide binding site mapping, residue conservation analysis, and binding energy calculations, we obtained two mutants (T204R and Y97R) with significantly improved catalytic activities of 1.56 × 10⁶ U/mg and 1.43 × 10⁶ U/mg, respectively. Building on the best-performing variant (T204R), stability-focused design yielded T204R/N206H, which extended the inactivation half-life at 45 °C by up to 1.4-fold without loss of activity. This engineered enzyme efficiently generates LMW-HA and o-HA with tunable size distributions under mild conditions. These findings expand the hyaluronidase toolbox with a recombinant PL8 enzyme, enabling controlled enzymatic production of LMW-HA and o-HA for biomedical and personal care applications.</p></div>","PeriodicalId":494,"journal":{"name":"Biotechnology for Biofuels","volume":"19 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2026-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1186/s13068-026-02772-4.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148019244","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":"Combined transcriptomic and proteomic analysis reveals the influence of sulfur availability on nitrogen and carbon metabolism and lipid accumulation in Tribonema minus (Xanthophyceae)","authors":"Jian Hong,&nbsp;Yijia Liu,&nbsp;Bohan Yu,&nbsp;Chengwu Zhang,&nbsp;Baoyan Gao","doi":"10.1186/s13068-026-02775-1","DOIUrl":"10.1186/s13068-026-02775-1","url":null,"abstract":"<div><p>Compared with single-cell microalgae, the filamentous microalgae <i>Tribonema</i> have stronger anti-predation ability and can be harvested more easily during large-scale production. To evaluate the potential of <i>Tribonema</i> as a raw material for biodiesel and bioproducts, this study conducted the comprehensive analysis of the biomass concentration and total lipid accumulation patterns of 12 <i>Tribonema</i> strains under nitrogen (N) and sulfur (S) nutritional regulation. Furthermore, by integrating multi-omics technologies, this study elucidated the potential mechanisms underlying lipid metabolism in <i>T. minus</i> under S-stress conditions. The results showed that under N concentration treatments (0, 3, and 18 mM), the biomass concentration of all 12 <i>Tribonema</i> strains initially increased and then decreased with increasing N concentration, while the total lipid content showed no significant correlation with N concentration. Under S concentration treatments (0, 0.3, and 1.2 mM), the biomass of all <i>Tribonema</i> species significantly increased with increasing S concentration. The total lipid and fatty acid content peaked at the lowest S concentration. A combined transcriptomic and proteomic analysis in <i>T. minus</i> revealed that under S-deficient conditions, the expression of genes and proteins related to N metabolism (<i>e.g.</i>, nitrate reductase and nitrite reductase) was downregulated, and those related to S metabolism (<i>e.g.</i>, ATP sulfurylase and APS kinase) were upregulated, thereby balancing intracellular levels of N and S to maintain normal growth and metabolism. The genes and proteins encoding the rate-limiting enzymes in the glycolysis pathway were upregulated, promoting pyruvate synthesis. The expression of genes and proteins associated with lipid synthesis (<i>e.g.</i>, DGAT and PDAT) was significantly upregulated, thereby promoting the accumulation of lipids. This study demonstrated that the regulation of S availability significantly impacts the metabolic network of <i>Tribonema</i>, providing theoretical support for its application in biodiesel and other high-value bioproducts.</p></div>","PeriodicalId":494,"journal":{"name":"Biotechnology for Biofuels","volume":"19 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2026-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1186/s13068-026-02775-1.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147990394","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":"Direct valorization of agricultural byproducts to vanillin by a synergistic Komagataella phaffii co-culture system","authors":"Difei Zhou,&nbsp;Yuji Yang,&nbsp;Yi Shao,&nbsp;Lina Sun,&nbsp;Geqi Qi,&nbsp;Menghui Tao,&nbsp;Zhen Li,&nbsp;Fengjiao Xin","doi":"10.1186/s13068-026-02770-6","DOIUrl":"10.1186/s13068-026-02770-6","url":null,"abstract":"<div><h3>Background</h3><p>The annual abundance of lignocellulosic agricultural byproducts poses a significant environmental burden. Leveraging this underutilized biomass to produce high-value, food-grade products represents a promising strategy for diversifying food ingredient sources and advancing the principles of the circular bioeconomy.</p><h3>Results</h3><p>Here, a novel <i>Komagataella phaffii</i> co-culture system was developed for integrated xylan hydrolysis and vanillin biosynthesis. In the upstream xylan hydrolysis module, overexpression of a novel multi-modular bifunctional xylanase/feruloyl esterase enabled the direct hydrolysis of xylans in agricultural byproducts to release ferulic acid (FA), thereby providing precursors for the downstream vanillin synthesis module. In the downstream module, FA was converted to vanillin via heterologous expression of feruloyl-CoA synthetase (FCS) and enoyl-CoA hydratase/aldolase (ECH). Subsequent optimization of strain inoculation ratios and carbon source composition in the co-culture system increased the titer of vanillin and its derivatives to 2.63 mM, achieving a 47.90% molar conversion rate from ultrafine-grinding corn cob (UGCC).</p><h3>Conclusions</h3><p>This study establishes a scalable platform for synthesizing aromatic compounds from low-cost lignocellulosic feedstocks, offering a strategic blueprint for valorizing agricultural residues.</p></div>","PeriodicalId":494,"journal":{"name":"Biotechnology for Biofuels","volume":"19 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2026-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1186/s13068-026-02770-6.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147977726","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Process optimisation for polyhydroxyalkanoates production with tailored hydroxyvalerate content from agri-food residues using mixed microbial cultures","authors":"Giovanna Pesante,&nbsp;Claudia Magonara,&nbsp;Alessia Zucca,&nbsp;Elvis Montagnese,&nbsp;Davide Bertasini,&nbsp;Gaia Salvatori,&nbsp;Lionel Nguemna Tayou,&nbsp;Luca Di Leva,&nbsp;Marianna Villano,&nbsp;David Bolzonella","doi":"10.1186/s13068-026-02773-3","DOIUrl":"10.1186/s13068-026-02773-3","url":null,"abstract":"&lt;div&gt;&lt;h3&gt;Background&lt;/h3&gt;&lt;p&gt;Polyhydroxyalkanoates (PHAs) are promising bio-based and biodegradable polymers that can contribute to the transition towards a circular bioeconomy, particularly when produced from renewable feedstocks. Nevertheless, the use of mixed microbial cultures (MMC) and real agri-food residues poses challenges related to substrate variability, process stability and control of polymer composition. In this study, a three-stage process was investigated to produce poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) from agri-food residues. The process consisted of: (i) acidogenic fermentation of cattle slurry and corn residues to generate a carboxylic acid (CA)-rich stream; (ii) microbial selection under feast–famine conditions to enrich PHA-accumulating microorganisms; and (iii) PHA accumulation in a fed-batch reactor. Two operational setups, differing in the pretreatment type, were compared to evaluate possible effects on PHA production: setup 1 used centrifuged fermentate, whereas setup 2 included an additional 0.22-µm filtration step.&lt;/p&gt;&lt;h3&gt;Results&lt;/h3&gt;&lt;p&gt;Acidogenic fermentation produced up to 18.6 gCOD/L of CAs, mainly acetic, butyric and propionic acids, with production strongly influenced by substrate ratio, hydraulic retention time and pH. The CA-rich fermented liquid was used to select MMC enriched with PHBV-accumulating microorganisms and to tune the PHBV composition during the subsequent accumulation phase. In setup 1, storage yield (mean 0.33 ± 0.23 gCOD&lt;sub&gt;PHA&lt;/sub&gt;/gCOD&lt;sub&gt;CA&lt;/sub&gt;), PHA titre (mean 0.81 ± 0.33 g/L) and intracellular PHA contents (4.0–21.0% w/w of cell dry weight) remained relatively low, likely due to the use of unfiltered fermentation effluent. In setup 2, the introduction of a filtration step and improved microbial selection led to higher and more stable conversion of CAs into PHAs, reaching mean storage yields of 0.78 ± 0.27 gCOD&lt;sub&gt;PHA&lt;/sub&gt;/gCOD&lt;sub&gt;CA&lt;/sub&gt;, mean PHA titre of 1.70 ± 0.44 g/L and intracellular PHA values up to 57.0% w/w. The hydroxyvalerate (HV) monomer content showed temporal variability, ranging from 14.0–32.0% w/w in setup 1 and from 13.0–35.0% w/w in setup 2, with values generally within or close to the target range required to improve polymer flexibility and processability. Microbial community analysis revealed a marked reduction in genus richness following feedstock filtration and the progressive dominance of specialised PHA-storing genera, indicating effective selection pressure under feast–famine operation and supporting the observed improvements in polymer accumulation.&lt;/p&gt;&lt;h3&gt;Conclusions&lt;/h3&gt;&lt;p&gt;Overall, the results indicate that MMC-based PHBV production from agri-food residues can achieve polymer contents comparable to those reported for similar systems using complex substrates, while highlighting the importance of feedstock pretreatment and process control. The study provides insights into the integration of acidogenic fermentation with MMC-based PHA production, ","PeriodicalId":494,"journal":{"name":"Biotechnology for Biofuels","volume":"19 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2026-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1186/s13068-026-02773-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147944079","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 artificial microbial consortia for efficient lactic acid fermentation from undetoxified hydrolysates: from induced niche succession in a dual Bacillus coagulans consortium to Pseudomonas putida-assisted system reinforcement","authors":"Jiaming Fu,&nbsp;Shuiping Ouyang,&nbsp;Shuai Liang,&nbsp;Chang Yu,&nbsp;Yuxuan Wu,&nbsp;Hongxiao Li,&nbsp;Zhaojuan Zheng,&nbsp;Jia Ouyang","doi":"10.1186/s13068-026-02771-5","DOIUrl":"10.1186/s13068-026-02771-5","url":null,"abstract":"<div><h3>Background</h3><p>Lignocellulosic biomass represents an ideal feedstock for biochemical production as a sustainable alternative to fossil resources. However, high concentrations of inhibitors inevitably generated during pretreatment—particularly phenolic compounds—severely impede microbial growth and metabolism, representing a major bottleneck in biorefining. In contrast to expensive physicochemical detoxification or single-strain strategies burdened by heavy metabolic loads, microbial co-culture systems employing division of labor offer a highly efficient and cost-effective novel pathway.</p><h3>Results</h3><p>This study developed a novel dual <i>Bacillus coagulans</i> co-culture system consisting of a phenolic acid decarboxylase (PAD)-overexpressing engineered strain, DSM1-25280, and a high-yield L-lactic acid (LA) producer, CC17B-1, capable of directly utilizing highly toxic lignocellulosic hydrolysates for high-titer LA production. Notably, overexpression of PAD in the engineered strain DSM1-25280 not only enhanced tolerance to phenolic acids but also significantly accelerated vanillin degradation. By establishing a sequential inoculation strategy and optimizing both inoculation ratios and intervals, the dual-strain system achieved a LA titer of 124.72 g/L from undetoxified corncob hydrolysates. Multidimensional association analysis suggested a strongly supported model of niche succession process within the system, transitioning from biodetoxification-mediated commensalism to competitive exclusion. Furthermore, we constructed an enhanced three-strain co-culture system by incorporating a sugar-metabolism-deficient engineered <i>Pseudomonas putida</i> KT2440 ZL as a heterologous aromatic scavenger. This system further elevated the LA titer to 146.00 g/L with a yield of 98.9%, ranking among the highest levels reported to date for LA production from undetoxified hydrolysates.</p><h3>Conclusions</h3><p>The constructed microbial co-culture system significantly enhances LA fermentation performance using undetoxified lignocellulosic hydrolysates, bypassing the need for physicochemical detoxification. Demonstrating exceptional modularity and robustness, this sequential co-culture strategy effectively overcomes the toxicity bottlenecks inherent in traditional bioconversion processes. Ultimately, this work not only validates the superiority of division of labor in valorizing complex feedstocks but also provides a novel approach for the efficient biomanufacturing of high-value chemicals from low-grade biomass.</p></div>","PeriodicalId":494,"journal":{"name":"Biotechnology for Biofuels","volume":"19 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2026-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1186/s13068-026-02771-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147847360","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":"Coupled succinic acid fermentation and biogas upgrading enabled by in situ product recovery","authors":"Ioannis Zacharopoulos,&nbsp;Antonio Grimalt-Alemany,&nbsp;Irini Angelidaki","doi":"10.1186/s13068-026-02766-2","DOIUrl":"10.1186/s13068-026-02766-2","url":null,"abstract":"<div><p>Biological CO₂-capture technologies, such as biogas upgrading, constitute essential tools toward decarbonization of the chemical and energy industries. Biological succinic acid production is one such process that naturally fixes CO₂ while producing an important platform chemical for the chemical and food industries. However, the high costs associated with biosuccinic acid production render it economically uncompetitive compared to petrochemically produced succinic acid. Here, we propose an integrated platform combining fermentation for succinic acid production from industrial waste streams with the successful upgrade of raw biogas from anaerobic digestion, which repurposes the process into a multi-product platform for increasing its economic viability. To reduce downstream separation costs, the fermentation process is also coupled with an in situ separation module that increases the performance of both the succinic acid fermentation and the biogas upgrade, reaching a CH₄ percentage of 93% in the final biogas and triggering a 32.5% increase in succinic acid production. Moreover, the use of the electrochemical module aids in the separation of succinic acid from the fermentation broth, resulting in 94.80% recovery of the succinic acid produced. All experiments were performed at semi-pilot scale.</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":"19 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2026-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1186/s13068-026-02766-2.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147847386","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":"Overexpression of endogenous galactolipases and an efflux transporter enhances the secretion of extracellular free fatty acids by Synechococcus elongatus PCC 7942","authors":"Kotoha Nishimoto,&nbsp;Tsubasa Furushima,&nbsp;Taro Kadowaki,&nbsp;Haruhiko Jimbo,&nbsp;Norifumi Yamamoto,&nbsp;Kazutaka Ikeda,&nbsp;Nobuyuki Takatani,&nbsp;Makiko Aichi,&nbsp;Tatsuo Omata,&nbsp;Yoshitaka Nishiyama","doi":"10.1186/s13068-026-02768-0","DOIUrl":"10.1186/s13068-026-02768-0","url":null,"abstract":"<div><h3>Background</h3><p>Cyanobacterial mutants engineered for production of free fatty acids (FFAs) are potentially useful sources of biofuels, since the FFAs are secreted into the extracellular medium. The exploitation of such mutants circumvents intracellular storage limits and minimizes energy-intensive downstream extraction processes. However, in addition to the inactivation of the endogenous <i>aas</i> gene (encoding acyl-ACP synthetase) to prevent recycling of FFAs, construction of the FFA-producing mutants requires introduction of a transgene for a thioesterase that generates FFAs from acyl-ACP. For exploitation of such mutants for biofuel production at the industrial level, in particular in countries with strict rules about dissemination of genetically modified organisms, it is essential to avoid introduction of foreign transgenes.</p><h3>Results</h3><p>Using the markerless mutagenesis method, we replaced an internal 3.0-kb segment of the <i>aas</i> gene of <i>Synechococcus elongatus</i> PCC 7942 with a DNA fragment that included the ORFs of the endogenous genes for galactolipases (<i>lipB</i> and/or <i>lipC</i>) and the RND-type FFA efflux transporter (<i>rndA1B1</i>), which were fused, respectively, to the endogenous <i>psbAII</i> promoter. Under strong light (200 µmol photons·m^-2·s^-1), the resultant engineered strains overexpressed both the galactolipase(s) and the FFA efflux-transporter RND and secreted significantly greater quantities of FFAs into an overlaid layer of isopropyl myristate than the parental <i>Δaas</i> strain. Cultivation at a suboptimal temperature (25 °C, as compared to 32 °C) further enhanced the production of FFAs. The most abundant secreted fatty acid was palmitoleic acid (16:1), confirming that FFAs originated primarily from the deacylation of membrane lipids. The titer, production rate, and yield of FFAs in the best-performing transformant (<i>Δaas::lipC-lipB-rndAB</i>) were similar to those reported previously for other genetically modified cyanobacteria that produce extracellular FFAs.</p><h3>Conclusions</h3><p>Co-overexpression of endogenous galactolipases and the RND transporter resulted in efficient extracellular secretion of FFAs in engineered <i>S. elongatus</i>. Our approach should facilitate investigations directed toward industrial applications, particularly in countries with strict regulations related to the dissemination of genetically modified organisms, and it provides a promising platform for the sustainable production of biofuel precursors.</p><h3>Graphic abstract</h3>\u0000<div><figure><div><div><picture><source><img></source></picture><span>The alternative text for this image may have been generated using AI.</span></div></div></figure></div></div>","PeriodicalId":494,"journal":{"name":"Biotechnology for Biofuels","volume":"19 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2026-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1186/s13068-026-02768-0.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147824620","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}