Journal of biotechnology最新文献_第2页

Aluminum phthalocyanine chloride loaded poly (lactic-co-glycolic acid) nanoparticles based photodynamic therapy for antibacterial and anticancer applications 负载聚乳酸-羟基乙酸-酞菁铝纳米粒子的光动力疗法在抗菌和抗癌中的应用。

IF 3.9 2区生物学 Q2 BIOTECHNOLOGY & APPLIED MICROBIOLOGY

Journal of biotechnology

Pub Date : 2025-12-18 DOI: 10.1016/j.jbiotec.2025.12.014

Anum Jamil , Aleena Zahid , Rafaqat Ali Khan , Muhammad Saleem , Syed Mujtaba Ul Hassan , Shahzad Anwar , Qura Tul Ain

Photodynamic therapy (PDT) and antibacterial Photodynamic therapy (aPDT) have become a viable non-invasive treatment against cancer and bacterial infections. By using light-activated photosensitizers (PS), PDT effectively destroys cancer cells and pathogenic bacteria. However, many PS agents, such as Aluminum Phthalocyanine chloride (AlPc), face limitations like poor solubility and low bioavailability. To overcome these challenges, AlPc-loaded PLGA nanoparticles (AlPc NPs) have been synthesized, where PS is encapsulated in Poly (lactic-co-glycolic acid) (PLGA) to enhance drug delivery and therapeutic efficacy. PLGA was selected for its well-established biomedical applications, including targeted drug delivery and antibacterial activity. This study focuses on synthesizing 200 nm AlPc NPs by using the single emulsion solvent evaporation method and characterizing them via spectroscopic and microscopic techniques. This study demonstrates that AlPc NPs' encapsulation efficiency is 82 % and drug loading efficiency is 10 %. The drug release profile shows 52 % release of AlPc NPs within 24 h. Cellular uptake of free AlPc and AlPc NPs was examined using confocal fluorescence imaging. The in vitro investigation used Hep-2C human laryngeal cancer cells to assess the dark and phototoxic effects of free AlPc and AlPc NPs for PDT. MTT results show that the cells treated with AlPc NPs had lower cell viability than cells treated with free AlPc at the same drug doses, which confirms improved efficacy of AlPc NPs. Moreover, AlPc NPs improved the antibacterial potential against the Escherichia coli (E. coli) bacterial strain and increased their bioavailability.

光动力疗法（PDT）和抗菌光动力疗法（aPDT）已成为一种可行的非侵入性治疗癌症和细菌感染的方法。PDT通过使用光活化光敏剂（PS），有效地破坏癌细胞和致病菌。然而，许多PS制剂，如酞菁氯化铝（AlPc），面临溶解度差和生物利用度低的局限性。为了克服这些挑战，人们合成了装载AlPc的PLGA纳米颗粒（AlPc NPs），其中PS被包裹在聚乳酸-羟基乙酸（PLGA）中，以增强药物传递和治疗效果。PLGA因其完善的生物医学应用而被选中，包括靶向药物输送和抗菌活性。本研究主要采用单乳液溶剂蒸发法制备了200nm的AlPc NPs，并对其进行了光谱和显微表征。本研究表明，AlPc NPs的包封效率为82%，载药效率为10%。药物释放谱显示AlPc NPs在24小时内释放52%。用共聚焦荧光成像检测游离AlPc和AlPc NPs的细胞摄取。体外研究采用Hep-2C人喉癌细胞，评估游离AlPc和AlPc NPs对PDT的暗毒性和光毒性作用。MTT结果显示，在相同药物剂量下，AlPc NPs处理的细胞活力低于游离AlPc处理的细胞，证实了AlPc NPs的疗效提高。此外，AlPc NPs提高了对大肠杆菌（E. coli）菌株的抗菌潜力，提高了其生物利用度。

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引用次数: 0

Systematic engineering of cell wall for improving single cell protein (SCP) production 提高单细胞蛋白（SCP）产量的细胞壁系统工程。

IF 3.9 2区生物学 Q2 BIOTECHNOLOGY & APPLIED MICROBIOLOGY

Journal of biotechnology

Pub Date : 2025-12-16 DOI: 10.1016/j.jbiotec.2025.12.011

Linhai Xie , Shuo Tian , Zhehao Jin , Tiantian Zou , Mingxin Chang , Hongting Tang , Tao Yu , Zhoukang Zhuang

As an emerging alternative protein, Single cell protein (SCP) has gained considerable traction in livestock feed applications. Furthermore, it presents substantial potential for replacing traditional dietary proteins for human consumption. Yet current research remains focused on strain screening with limited advances in cellular metabolic engineering. Due to the complexity of protein synthesis and processing, enhancing the SCP production efficiency in microbial chassis remains a major challenge. Here, we present a metabolic engineering approach to systematic engineer the cell wall of Saccharomyces cerevisiae for improving SCP production. In this study, we constructed a strain by gene modifications of genes related to cell wall biogenesis and associated signaling pathways, achieving a 32.6 % increase in cellular protein content. Additionally, comparative transcriptomics analysis uncovered the regulatory mechanism whereby remodeling of carbon and nitrogen metabolism governs cellular protein biosynthesis, providing new insight for the rational design of microbial cell factories with enhanced protein content.

单细胞蛋白（Single cell protein， SCP）作为一种新兴的替代蛋白，在家畜饲料中得到了广泛的应用。此外，它为人类消费提供了替代传统膳食蛋白质的巨大潜力。然而，目前的研究仍然集中在菌株筛选上，细胞代谢工程的进展有限。由于蛋白质合成和加工的复杂性，提高微生物底盘的SCP生产效率仍然是一个主要挑战。在这里，我们提出了一种代谢工程方法来系统地改造酿酒酵母的细胞壁，以提高SCP的产量。在这项研究中，我们通过对细胞壁生物发生相关基因和相关信号通路进行基因修饰构建了一个菌株，使细胞蛋白含量增加了32.6%。此外，比较转录组学分析揭示了碳氮代谢重塑控制细胞蛋白质生物合成的调控机制，为合理设计提高蛋白质含量的微生物细胞工厂提供了新的见解。

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引用次数: 0

Engineered BDH–NOx co-expression in Escherichia coli enables highly efficient in vivo cascade catalysis for the transformation of racemic epoxides to α-hydroxyketones 改造后的BDH-NOx在大肠杆菌中的共表达能够高效地在体内级联催化将外消旋环氧化合物转化为α-羟基酮。

IF 3.9 2区生物学 Q2 BIOTECHNOLOGY & APPLIED MICROBIOLOGY

Journal of biotechnology

Pub Date : 2025-12-16 DOI: 10.1016/j.jbiotec.2025.12.012

Bochun Hu , Xiaoqi Xi , Qianjin Hou , Jiaxin Ou , Xiaoxuan Shen , Zining Wang , Jiahui Zhao , Cunduo Tang , Jihong Huang

To eliminate the requirement for pyruvate supplementation and to avoid lactate accumulation, a multi-enzyme cascade was systematically restructured by replacing lactate dehydrogenase (LDH) with water-forming NADH oxidase (EfNOx). In this revised system, RpEH^L360V catalyzed the enantioconvergent hydrolysis of rac-4-chlorostyrene oxide (rac-1a) to (R)-1-(4-chlorophenyl)-1,2-ethanediol (1b), followed by stereoselective oxidation of (R)-1b to 4’-chloro-2-hydroxyacetophenone (1c) by BsBDHA^{I49L/V266L/G292A}. Concurrently, EfNOx reduced molecular oxygen to water, regenerating NAD⁺ and sustaining redox balance. To further enhance intracellular cofactor turnover, BsBDHA^{I49L/V266L/G292A} and EfNOx were co-expressed in Escherichia coli, generating the recombinant strain E. coli/Cbn. Through single-factor and L9(3³) orthogonal array optimization, the one-pot in vivo cascade achieved maximal efficiency with lyophilized whole cells of E. coli/rpeh^L360V (5 mg DCW/mL) and E. coli/Cbn (35 mg DCW/mL) in sodium phosphate buffer (10 mM, pH 7.0) containing 5 mM NAD⁺ and 5 % (v/v) Tween-20 at 25 °C for 8 h under controlled agitation and aeration. Under these conditions, 25 mM rac-1a was converted to 1c with a yield of 92.1 % and a space-time yield (STY) of 2.9 mmol/L/h, representing a 3.7-fold increase relative to the original LDH-based system. The applicability of the cascade was further demonstrated using additional substrates (rac-2a to rac-7a), yielding the corresponding α-hydroxyketones at 39.1–94.5 % with STYs of 1.2–3.0 mmol/L/h. These findings establish BDH–NOx co-expression as a robust strategy for cofactor self-sufficiency and provide a scalable framework for the efficient in vivo synthesis of structurally diverse α-hydroxyketones.

为了消除对丙酮酸补充的需求并避免乳酸积累，通过用形成水的NADH氧化酶（EfNOx）取代乳酸脱氢酶（LDH）来系统地重组多酶级联。在改进后的体系中，RpEHL360V催化rac-4-氯苯乙烯氧化物（rac-1a）对映聚合水解为(R)-1-（4-氯苯基）-1,2-乙二醇（1b），随后BsBDHAI49L/V266L/G292A将(R)-1b立体选择性氧化为4'-氯-2-羟基苯乙酮（1c）。同时，EfNOx将分子氧还原为水，再生NAD+并维持氧化还原平衡。为了进一步促进细胞内辅助因子的转换，BsBDHAI49L/V266L/G292A和EfNOx在大肠杆菌中共表达，生成重组菌株E. coli/Cbn。通过单因素和L9（33）正交阵列优化，大肠杆菌/rpehL360V （5mg DCW/mL）和大肠杆菌/Cbn （35mg DCW/mL）冻干全细胞在含有5mM NAD+和5% (v/v) Tween-20的磷酸钠缓冲液（10mM, pH 7.0）中，在25°C、可控搅拌和曝气条件下，在8小时内进行一锅体内级联，效率最高。在此条件下，25mM rac-1a转化为1c，产率为92.1%，空时产率（STY）为2.9mmol/L/h，比原来的ldh体系提高了3.7倍。利用其他底物（rac-2a至rac-7a）进一步验证了该级联的适用性，得到相应的α-羟基酮，产率为39.1%至94.5%，STYs为1.2至3.0mmol/L/h。这些发现证实了BDH-NOx共表达是一种辅助因子自给自足的强大策略，并为结构多样的α-羟基酮的高效体内合成提供了可扩展的框架。

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引用次数: 0

Soft-sensing strategy for real-time biomass and poly(3-hydroxybutyrate) estimation in methanotrophic cultures using dissolved oxygen and base addition signals 利用溶解氧和碱添加信号实时估算甲烷营养培养物生物量和聚（3-羟基丁酸）的软测量策略。

IF 3.9 2区生物学 Q2 BIOTECHNOLOGY & APPLIED MICROBIOLOGY

Journal of biotechnology

Pub Date : 2025-12-16 DOI: 10.1016/j.jbiotec.2025.12.013

Seungyeon Cho , Kyutae Jung , Yoojin Shin , Inseo Kim , Seong-Hoon Jun , Hyo Jin Hong , Jeongwoo Lee , Jinwon Lee , Jeong-Geol Na

Real-time estimation of microbial biomass and product formation is crucial for effective monitoring and control of bioprocesses. In this study, we present a generalized soft-sensing algorithm that utilizes commonly available dissolved oxygen (DO) and base addition signals to estimate both total cell concentration and intracellular poly(3-hydroxybutyrate) (PHB) content. Total cell concentration was calculated using a DO-based oxygen balance equation, while PHB accumulation was inferred from a nitrogen balance framework, in which nitrogen consumption was estimated based on the frequency of base additions under pH-stat control. We validated the algorithm using methane-fed cultures of Methylocystis sp. MJC1, demonstrating high accuracy in predicting total biomass concentration across various media compositions and operational conditions, provided that ammonium was used as the nitrogen source. Notably, PHB concentrations were reliably estimated in real time by subtracting the non-PHB biomass (derived from base addition signals) from the DO-based total biomass. Although some deviations in PHB predictions were observed, these were attributed to imperfect correlations between nitrogen consumption and pH behavior. The method requires minimal data preprocessing and has low computational demands, making it well-suited for real-time applications in gas fermentation as well as other aerobic bioprocesses. This soft-sensing strategy offers a simple, robust, and cost-effective approach for online monitoring of microbial growth and product formation.

微生物生物量和产物形成的实时估计对于有效监测和控制生物过程至关重要。在这项研究中，我们提出了一种广义的软测量算法，该算法利用常用的溶解氧（DO）和碱添加信号来估计细胞总浓度和细胞内聚（3-羟基丁酸盐）（PHB）含量。总细胞浓度使用基于do的氧平衡方程计算，而PHB积累是从氮平衡框架推断的，其中氮消耗是根据ph值控制下的碱基添加频率估计的。我们用甲烷培养的Methylocystis sp. MJC1验证了该算法，证明了在不同培养基组成和操作条件下，只要使用铵作为氮源，该算法在预测总生物量浓度方面具有很高的准确性。值得注意的是，通过从基于do的总生物量中减去非PHB生物量（来自碱添加信号），可以可靠地实时估计PHB浓度。虽然在PHB预测中观察到一些偏差，但这些偏差归因于氮消耗与pH行为之间的不完全相关性。该方法需要最小的数据预处理和低计算需求，使其非常适合实时应用于气体发酵以及其他好氧生物过程。这种软测量策略为微生物生长和产品形成的在线监测提供了一种简单、稳健、经济的方法。

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引用次数: 0

AbrB and ResD negatively regulate locillomycin synthesis in Bacillus velezensis Bs916 by binding to the flanking sequences of transcription start sites abb和ResD通过与转录起始位点的侧翼序列结合，负向调控蓝芽孢杆菌Bs916中locillomycin的合成。

IF 3.9 2区生物学 Q2 BIOTECHNOLOGY & APPLIED MICROBIOLOGY

Journal of biotechnology

Pub Date : 2025-12-16 DOI: 10.1016/j.jbiotec.2025.12.010

Xiaohua Wang , HanWen Shen , Peng Zhang , Zhongzheng Ji , Xiaoxia Xu , Faxiang Wan , Xiulian Yin , Qingyun Bai , Liangcheng Du , Jiasong Jiang , Chuping Luo

Locillomycin, a cyclic lipopeptide produced by Bacillus velezensis Bs916, has been proven to have strong antimicrobial activity and low hemolytic activity. However, its low yield has become a significant obstacle for large-scale application. To identify the regulatory factors of locillomycin and obtain its high-yield strains through gene knockout, the transcriptional landscape of loc gene cluster was elucidated, and ResD and AbrB were identified as potential transcription regulators of the locillomycin biosynthesis gene cluster. EMSA and DNase Ⅰ footprinting results showed that AbrB tended to bind to A + T-rich fragments and exhibited extensive DNA-binding properties, being able to directly associate with the promoter, 5′ UTR, and coding region of the loc gene cluster. In contrast, the binding of ResD was confined to the promoter sequence upstream of the loc transcription start site, spanning from −480 to −456. To verify their impact on locillomycin production, mutants ΔresD, ΔabrB and ΔresD+abrB were constructed using homologous recombination techniques, and HPLC analyses revealed substantial yield enhancements: 1.6-fold for ΔresD, 2.4-fold for ΔabrB, and a striking 5.8-fold for ΔresD+abrB mutants. In addition, the RT-qPCR results further confirmed that ResD and AbrB were indeed negative regulatory factors for locillomycin. Our results gave rise to a better understanding of the biosynthetic regulation of locillomycin and provided theoretical guidance for the construction of high yielding strains of lipopeptides.

Locillomycin是由velezensis Bs916产生的一种环状脂肽，具有较强的抗菌活性和较低的溶血活性。然而，其产量低已成为大规模应用的重大障碍。为了确定红霉素的调控因子并通过基因敲除获得其高产菌株，我们对loc基因簇的转录格局进行了阐明，并确定了ResD和AbrB是红霉素生物合成基因簇的潜在转录调控因子。EMSA和DNaseⅠ足迹分析结果表明，AbrB倾向于与富含A + t的片段结合，并表现出广泛的dna结合特性，能够直接与loc基因簇的启动子、5' UTR和编码区结合。相比之下，ResD的结合仅限于loc转录起始位点上游的启动子序列，从-480到-456。为了验证它们对红霉素生产的影响，利用同源重组技术构建了突变体ΔresD、ΔabrB和ΔresD+abrB， HPLC分析显示产量大幅提高：ΔresD的产量提高了1.6倍，ΔabrB的产量提高了2.4倍，ΔresD+abrB突变体的产量提高了惊人的5.8倍。此外，RT-qPCR结果进一步证实了ResD和AbrB确实是locillomycin的负调控因子。本研究结果为进一步了解红霉素的生物合成调控提供了理论依据，并为构建高产脂肽菌株提供了理论指导。

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引用次数: 0

Semi-rational design of a thermostable O-glycosyltransferase from Glycyrrhiza uralensis for efficient conversion of protopanaxadiol 甘草o -糖基转移酶的半合理设计，用于高效转化原嘌呤二醇。

IF 3.9 2区生物学 Q2 BIOTECHNOLOGY & APPLIED MICROBIOLOGY

Journal of biotechnology

Pub Date : 2025-12-16 DOI: 10.1016/j.jbiotec.2025.12.008

Jiajie Ding, Zhiying Ding, Yuan Liao, Jiajie Chen, Kai Chen, Honghua Jia, Yan Li

Ginsenoside Rh2 (3-β-O-Glc-protopanaxadiol) and Rg3 (20-β-O-Glc-3-β-O-Glc-protopanaxadiol) are rare tetracyclic triterpenoids known for their significant medicinal properties, including antitumor and anti-inflammatory activities. The glycosylation of the C3-OH and C20-OH groups of protopanaxadiol (PPD) by UDP-glycosyltransferase (UGT) is a crucial biological modification that contributes to the extensive structural and functional diversity of PPD-type ginsenosides. In this study, we identified a 3-O-glycosyltransferase (GuUGT73F15) from Glycyrrhiza uralensis, which specifically glycosylates the C3-OH of PPD to produce ginsenoside Rh2. Through site-directed mutagenesis and combinatorial active-site engineering, an optimized variant, GuUGT73F15_{H47P/R84K/N211T}, exhibiting a 2.65-fold increase in catalytic efficiency (k_cat/K_m) for PPD conversion and a remarkable 26.7-fold extension in half-life (t_1/2 = 292.47 min at 37 °C) compared to the wild-type enzyme. Molecular docking and dynamics simulations provided mechanistic insights into the enhanced activity and thermostability of the enzyme. Furthermore, this variant was combined with a glycosyltransferase variant (UGT29_{R91M/D184M/A287V/A342L}) and sucrose synthases, resulting in a high-level production of Rg3 (19.88 mM, 15.61 g/L) in a 24-h fed-batch reaction using PPD as the substrate. This study presents an efficient and thermostable O-glycosyltransferase for the targeted biosynthesis of PPD-type ginsenosides.

人参皂苷Rh2 （3-β-O-Glc-protopanaxadiol）和Rg3 （20-β-O-Glc-3-β-O-Glc-protopanaxadiol）是罕见的四环三萜，具有重要的抗肿瘤和抗炎活性。原人参二醇（PPD）的C3-OH和C20-OH基团被udp -糖基转移酶（UGT）糖基化是PPD型人参皂苷广泛的结构和功能多样性的关键生物学修饰。在本研究中，我们从甘草中鉴定了一种3- o -糖基转移酶（GuUGT73F15），该酶特异性地将PPD的C3-OH糖基化以产生人参皂苷Rh2。通过位点定向诱变和组合活性位点工程，优化后的变体GuUGT73F15H47P/R84K/N211T对PPD转化的催化效率（kcat/Km）比野生型提高了2.65倍，半衰期延长了26.7倍（t1/2 = 292.47min, 37℃）。分子对接和动力学模拟为增强酶的活性和热稳定性提供了机制见解。此外，该变体与糖基转移酶变体（UGT29R91M/D184M/A287V/A342L）和蔗糖合酶偶联，以PPD为底物，在24小时的间歇加料反应中获得了高水平的Rg3 （19.88mM, 15.61g/L）。本研究提出了一种高效、耐热的o -糖基转移酶，用于ppd型人参皂苷的靶向生物合成。

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引用次数: 0

Cell specific nutrient feeding in perfusion mode enhances hMSC growth in stirred tank bioreactor process 在搅拌槽生物反应器中，灌注模式下细胞特异性营养物的饲喂可促进hMSC的生长。

IF 3.9 2区生物学 Q2 BIOTECHNOLOGY & APPLIED MICROBIOLOGY

Journal of biotechnology

Pub Date : 2025-12-15 DOI: 10.1016/j.jbiotec.2025.12.006

Johanna Pechan , Kristina Engström , Nora Mac Key , Lina Sörvik , Véronique Chotteau

Human Mesenchymal Stromal Cells (hMSCs) are a safe option for allogeneic cell therapy across various diseases, but their manufacturing process requires improvement to broaden accessibility. In this study, a state-of-the-art planar multi-vessel process was transferred to a stirred tank bioreactor using microcarriers to support the growth of adherent cells. The frequent medium exchange strategy from planar culture guided the design of the bioreactor process. However, complete medium changes in the bioreactor resulted in limited cell expansion and higher glucose consumption compared to planar culture. To enhance expansion, a 0.1 L perfusion bioreactor was tested, enabling continuous medium exchange. Three perfusion approaches were evaluated: (1) maintaining a target cell-specific glucose consumption rate, (2) varying the perfusion rate, and (3) applying a cell-specific perfusion rate. Implementing targeted glucose feeding (TAFE) reduced lactate production, while increasing perfusion rates improved cell density. The highest expansion was achieved using a cell-specific perfusion rate of 5 nL cell⁻¹ day⁻¹ combined with a target glucose consumption rate (q_glc) of 15 pmol cell⁻¹ day⁻¹, resulting in a 5.4-fold higher expansion factor than daily medium changes in stirred tank bioreactors. This optimized process represents a key advancement toward producing clinically relevant quantities of hMSCs.

人间充质基质细胞（hMSCs）是异体细胞治疗多种疾病的安全选择，但其制造工艺需要改进以扩大可及性。在本研究中，将最先进的平面多容器工艺转移到搅拌槽生物反应器中，使用微载体支持贴壁细胞的生长。平面培养的频繁介质交换策略指导了生物反应器工艺的设计。然而，与平面培养相比，生物反应器中完全改变培养基导致细胞扩增有限，葡萄糖消耗更高。为了增强膨胀，我们测试了0.1L的灌注生物反应器，以实现连续的介质交换。评估了三种灌注方法：(1)维持靶细胞特异性葡萄糖消耗率，(2)改变灌注率，(3)应用细胞特异性灌注率。实施靶向葡萄糖喂养（TAFE）减少乳酸生成，而增加灌注率提高细胞密度。当细胞特异性灌注率为5 nL细胞-1天-1，目标葡萄糖消耗率（qglc）为15 pmol细胞-1天-1时，达到了最高的扩增率，其扩增系数比搅拌槽生物反应器中每日培养基变化高5.4倍。这个优化的过程代表了生产临床相关数量的hMSCs的关键进展。

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引用次数: 0

Enhancing oxidative stress defense to improve docosahexaenoic acid production in Schizochytrium sp. HX-308 增强氧化应激防御提高Schizochytrium sp. HX-308二十二碳六烯酸产量

IF 3.9 2区生物学 Q2 BIOTECHNOLOGY & APPLIED MICROBIOLOGY

Journal of biotechnology

Pub Date : 2025-12-12 DOI: 10.1016/j.jbiotec.2025.12.005

Chunxiao Yan , Shuai Zhang , Zhihao Huang , Fei Du , Qian Xu , Wang Ma , Guang Yang , Xiaoman Sun

As an excellent host for docosahexaenoic acid (DHA) biosynthesis, Schizochytrium sp. still faces inherent limitations in DHA yield due to oxidative damage induced by reactive oxygen species (ROS). To effectively reduce the ROS levels, the optimal combination of mixed antioxidants (52.95 mg L⁻¹ phytic acid, 32.00 mg L⁻¹ licorice extract, 36.28 mg L⁻¹ ascorbic acid palmitate) was selected by single factor experiment combined with response surface optimization. The DHA titer increased from 24.0 g L⁻¹ to 33.5 g L⁻¹. However, exogenous addition of antioxidants results in increased the cost of DHA production. Enhancing the intracellular antioxidant capacity through gene engineering has become another feasible strategy. Transcriptome analysis indicated that the transcriptional levels of antioxidant-related genes SOD1 (superoxide dismutase), APX5 (ascorbic acid peroxidase), and GST3 (glutathione S-transferase) were significantly upregulated during DHA biosynthesis. Then, the engineered strain SOD1-APX5-GST3–2 was constructed by overexpressing the three genes, and the DHA and lipid titers were 33.1 g L⁻¹ and 64.1 g L⁻¹, respectively. Scale-up in a 5 L bioreactor obtained 32.5 g L⁻¹ DHA and 63.5 g L⁻¹ lipid, and the ROS level decreased by 30.5 %, demonstrating engineered strain's stability and laying the foundation for industrial-scale production. This study verified that reducing ROS levels promoted DHA biosynthesis in Schizochytrium sp. from the two dimensions of exogenous antioxidants and gene engineering, which provided novel insights for industrial lipid production.

Schizochytrium sp.作为二十二碳六烯酸（二十二碳六烯酸，DHA）生物合成的优良宿主，由于活性氧（reactive oxygen species， ROS）诱导的氧化损伤，其DHA产量仍存在固有的局限性。为有效降低ROS水平，通过单因素试验结合响应面优化，筛选出混合抗氧化剂（52.95mg -1植酸、32.00mg -1甘草提取物、36.28mg -1抗坏血酸棕榈酸酯）的最佳组合。DHA滴度由24.0gL-1提高到33.5gL-1。然而，外源添加抗氧化剂会导致DHA生产成本的增加。通过基因工程增强细胞内抗氧化能力已成为另一种可行的策略。转录组分析表明，抗氧化相关基因SOD1（超氧化物歧化酶）、APX5（抗坏血酸过氧化物酶）和GST3（谷胱甘肽s -转移酶）的转录水平在DHA生物合成过程中显著上调。通过过表达这3个基因构建工程菌株SOD1-APX5-GST3-2，其DHA滴度为33.1gL-1，脂质滴度为64.1gL-1。在5L生物反应器中放大后，得到了32.5gL-1 DHA和63.5gL-1脂质，ROS水平下降了30.5%，证明了工程菌株的稳定性，为工业规模生产奠定了基础。本研究从外源抗氧化剂和基因工程两个维度验证了ROS水平的降低促进了Schizochytrium sp. DHA的生物合成，为工业脂质生产提供了新的见解。

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引用次数: 0

Next level of p-phenylene diisothiocyanate-based covalent immobilization of β-D-galactosidase: Technical optimization as an application 基于对苯二异硫氰酸酯的β-d-半乳糖苷酶共价固定化的新水平：技术优化应用。

IF 3.9 2区生物学 Q2 BIOTECHNOLOGY & APPLIED MICROBIOLOGY

Journal of biotechnology

Pub Date : 2025-12-10 DOI: 10.1016/j.jbiotec.2025.12.004

Tabea L. Boehme , Bernadette Straub , Anja Oberle , Ursula Eschenhagen , Magnus S. Schmidt

In this study, a continuous lactose hydrolysis process in a fixed-bed reactor was developed using β-galactosidase covalently immobilized on resin beads via 1,4-phenylenediisothiocyanate (PDC) as linker. Process conditions, including temperature, enzyme loading, perfusion speed, and repeated perfusion of the same substrate solution were systematically varied. The highest glucose yields were obtained at 55 °C, with increased yields observed at low perfusion speeds, high enzyme loadings, and upon repeated perfusions. Under optimized cycle perfusion over 72 h, final lactose conversion reached approximately 90 % at 37 °C and 80 % at 22 °C. A hydrolysis process in a fixed-bed reactor was successfully established, although further optimization is required.

本研究以1,4-苯二异硫氰酸酯（PDC）为连接剂，将β-半乳糖苷酶共价固定在树脂珠上，建立了固定床反应器中乳糖连续水解工艺。工艺条件，包括温度，酶载量，灌注速度，重复灌注相同的底物溶液系统地改变。在55°C时获得最高葡萄糖产量，在低灌注速度、高酶负荷和重复灌注时观察到产量增加。在优化循环灌注超过72h的情况下，最终乳糖转化率在37°C时达到约90%，在22°C时达到80%。在固定床反应器中成功建立了水解过程，但需要进一步优化。

引用次数: 0

Antibacterial effects and mechanisms of fisetin-β-cyclodextrin complex under UVA light against Escherichia coli O157:H7 非瑟酮-β-环糊精配合物在UVA光下对大肠杆菌O157:H7的抑菌作用及其机制

IF 3.9 2区生物学 Q2 BIOTECHNOLOGY & APPLIED MICROBIOLOGY

Journal of biotechnology

Pub Date : 2025-12-06 DOI: 10.1016/j.jbiotec.2025.12.003

Tao Liu , Yuzhang Zhu , Jiahui Wang , Kun Lin , Xuan Zhang , Huawei Ma , Chaonan Kong , Wei Cai , Lifang Yang , Mingguo Jiang

The development of natural product photosensitizers was a critical cornerstone for applying photodynamic antimicrobial technology in the food industry. The objective of this study was to fabricate complex of fisetin-β-cyclodextrin (FIT-β-CD), explore their photodynamic antimicrobial efficacy and mechanisms, and characterize it through infrared spectroscopy and X-ray diffraction. The results indicatde that this method can produce good dispersibility and water solubility of FIT-β-CD complex.The photodynamic impact of FIT-β-CD was assessed by examining alterations in reactive oxygen species (ROS) production.The results demonstrated that FIT-β-CD can rapidly generate ROS under UVA, with hydrogen peroxide production being 3.73 times higher than in dark conditions. The antimicrobial efficacy of FIT-β-CD against Escherichia coli O157:H7 (E.coli O157:H7) was evaluated based on bactericidal efficacy, cell membrane damage, DNA and protein damage, motility changes, biofilm formation, and extracellular polysaccharide production. In addition, gene expression analysis by RT-qPCR showed its significant inhibition on the two-component system (TCS) and quorum sensing system (QS). The results indicated that FIT-β-CD exhibited efficient, sensitive photodynamic, and antibacterial properties against E.coli O157:H7, making it a novel photosensitizer. These findings imply potential new applications of fisetin in the field of food antimicrobial agents.

天然产物光敏剂的开发是光动力抗菌技术在食品工业中应用的重要基石。本研究的目的是制备非瑟酮-β-环糊精配合物（FIT-β-CD），探讨其光动力抗菌效果和机制，并通过红外光谱和x射线衍射对其进行表征。结果表明，该方法制备的FIT-β-CD配合物具有良好的分散性和水溶性。通过检测活性氧（ROS）产生的变化来评估FIT-β-CD的光动力学影响。结果表明，在UVA条件下，FIT-β-CD可以快速生成ROS，过氧化氢产量是暗条件下的3.73倍。通过对大肠杆菌O157:H7 （E.coli O157:H7）的杀菌效果、细胞膜损伤、DNA和蛋白质损伤、运动改变、生物膜形成和胞外多糖生成等指标评价FIT-β-CD对大肠杆菌O157:H7的抑菌效果。此外，RT-qPCR基因表达分析显示其对双组分系统（TCS）和群体感应系统（QS）有显著抑制作用。结果表明，FIT-β-CD对大肠杆菌O157:H7具有高效、灵敏的光动力学和抗菌性能，是一种新型光敏剂。这些发现暗示了非瑟酮在食品抗菌剂领域的潜在新应用。

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