L-缬氨酸发酵生产的育种思路及发酵条件优化策略

L-缬氨酸在医药及饲料领域中有着广泛的用途,根据L缬氨酸的生物合成途径及其代谢调节机制,利用代谢调控理论,重点阐述了L缬氨酸生产菌的育种思路及培养条件的优化,为缬氨酸发酵生产提供理论指导。     

发酵法生产长链二元酸研究进展

发酵法生产长链二元酸相对于化工法而言有着无可比拟的优势。本文综述了发酵法生产长链二元酸的微生物源、产酸机理、产酸条件和产物分离技术等方面的研究进展 ,并简要介绍了其工业应用前景。     

工业微生物酸胁迫的耐受机制及改造途径

工业微生物在发酵生产过程中会面对发酵环境和自身产生的各类酸性物质,而这些酸性物质会影响工业微生物的生长和代谢,即产生酸胁迫。微生物通过调控胞内质子浓度、保护和修复生物大分子、改变细胞膜组分以及整体水平调控等耐受机制来应对酸胁迫。结合酸胁迫的各种耐受机制,利用自然筛选和人工改造的方法提高工业微生物的抗酸胁迫能力,为构建出更能适应工业生产条件的菌株提供理论依据。     

微生物法生产二羟基丙酮的研究进展

以下综述了微生物发酵法制备二羟基丙酮的研究进展。利用微生物发酵法生产二羟基丙酮比化学合成法具有更大的优势,氧化葡萄糖酸杆菌是二羟基丙酮工业发酵生产中最有应用价值的菌株。发酵过程中底物、产物、氧气、菌体量等各种因素都会对二羟基丙酮产量产生影响,在各种发酵方式中反复流加工艺和固定化发酵工艺最有前途。重组菌株的构建和发酵工艺的优化是将来微生物发酵生产二羟基丙酮的发展方向。     

发酵法生产生物表面活性剂

发酵法生产表面活性剂相对于化工法而言有着无可比拟的优势。综述了发酵法生产生物表面活性剂的微生物源、发酵机理、发酵条件和产物分离技术等方面的研究进展 ,并简要介绍了其工业应用前景。     

不同育种技术在乙醇及丁醇高产菌株选育中的应用

利用微生物发酵进行能源物质的生产是开发新型可再生能源的重要手段。在工业化生产过程中,由于高温、渗透压及产物毒性效应等不良环境因素,常导致生产菌株的多种重要生理功能发生改变,从而降低产物转化效率。因此,获取高产及抗逆性强的优良菌株是提高生物燃料工业化进程的重要途径之一。本文以乙醇与丁醇生产菌株为研究对象,系统阐述当前提高生产菌株发酵性能的各种育种手段,并对其在工业化生产过程中所面临的机遇与挑战进行简要评述。     

Bioethanol from synthesis gas

A new technology for obtaining ethanol through the fermentation of synthesis gas, which is produced from lignocellulose by special bacteria-acidogenes is discussed in the review. The technology has a set of fundamental advantages compared to traditional methods of fermentation of sugars: versatility and high yield of alcohol. In 2012–2013, in the United States and China, industrial plants using this technology will be commissioned.     

Monitoring complex media fermentations with near-infrared spectroscopy: comparison of different variable selection methods

Near-infrared spectroscopy (NIRS) is known to be a suitable technique for rapid fermentation monitoring. Industrial fermentation media are complex, both chemically (ill-defined composition) and physically (multiphase sample matrix), which poses an additional challenge to the development of robust NIRS calibration models. We investigated the use of NIRS for at-line monitoring of the concentration of clavulanic acid during an industrial fermentation. An industrial strain of Streptomyces clavuligerus was cultivated at 200-L scale for the production of clavulanic acid. Partial least squares (PLS) regression was used to develop calibration models between spectral and analytical data. In this work, two different variable selection methods, genetic algorithms (GA) and PLS-bootstrap, were studied and compared with models built using all the spectral variables. Calibration models for clavulanic acid concentration performed well both on internal and external validation. The two variable selection methods improved the predictive ability of the models up to 20%, relative to the calibration model built using the whole spectra.     

Identification of Dekkera bruxellensis as a major contaminant yeast in continuous fuel ethanol fermentation

AIMS: To identify and characterize the main contaminant yeast species detected in fuel-ethanol production plants in Northeast region of Brazil by using molecular methods. METHODS AND RESULTS: Total DNA from yeast colonies isolated from the fermentation must of industrial alcohol plants was submitted to PCR fingerprinting, D1/D2 28S rDNA sequencing and species-specific PCR analysis. The most frequent non-Saccharomyces cerevisiae isolates were identified as belonging to the species Dekkera bruxellensis, and several genetic strains could be discriminated among the isolates. The yeast population dynamics was followed on a daily basis during a whole crop harvesting period in a particular industry, showing the potential of D. bruxellensis to grow faster than S. cerevisiae in industrial conditions, causing recurrent and severe contamination episodes. CONCLUSIONS: The results showed that D. bruxellensis is one of the most important contaminant yeasts in distilleries producing fuel-ethanol from crude sugar cane juice, specially in continuous fermentation systems. SIGNIFICANCE AND IMPACT OF THE STUDY: Severe contamination of the industrial fermentation process by Dekkera yeasts has a negative impact on ethanol yield and productivity. Therefore, early detection of D. bruxellensis in industrial musts may avoid operational problems in alcohol-producing plants.     

Selection of Penicillium chrysogenum--producer of penicillin with several valuable technologic features]

The efficiency of the routine methods for improvement of P. chrysogenum providing specific selection by several features with testing one of them was studied. A new highly potent strain of P. chrysogenum producing phenoxymethylpenicillin was isolated. The strain is characterized by a shorter fermentation cycle, lower viscosity of the fermentation broth and capacity for synthesizing 32,600 units/ml of phenoxymethylpenicillin under industrial conditions (in a lactose medium) by the 97th hour of the cultivation in fermenters with energy consumption of 1.3 kW. The increased amylolytic activity of the strain and the decreased viscosity of the fermentation broth provided using of the fermentation media containing 3.5 per cent of corn meal.     

Comparative proteome analysis of robust <Emphasis Type="Italic">Saccharomyces cerevisiae</Emphasis> insights into industrial continuous and batch fermentation

A robust Saccharomyces cerevisiae strain has been widely applied in continuous and batch/fed-batch industrial fermentation. However, little is known about the molecular basis of fermentative behavior of this strain in the two realistic fermentation processes. In this paper, we presented comparative proteomic profiling of the industrial yeast in the industrial fermentation processes. The expression levels of most identified protein were closely interrelated with the different stages of fermentation processes. Our results indicate that, among the 47 identified protein spots, 17 of them belonging to 12 enzymes were involved in pentose phosphate, glycolysis, and gluconeogenesis pathways and glycerol biosynthetic process, indicating that a number of pathways will need to be inactivated to improve ethanol production. The differential expressions of eight oxidative response and heat-shock proteins were also identified, suggesting that it is necessary to keep the correct cellular redox or osmotic state in the two industrial fermentation processes. Moreover, there are significant differences in changes of protein levels between the two industrial fermentation processes, especially these proteins associated with the glycolysis and gluconeogenesis pathways. These findings provide a molecular understanding of physiological adaptation of industrial strain for optimizing the performance of industrial bioethanol fermentation. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

酵母发酵生产辅酶Q10提取方法研究进展

辅酶Q10是存在于哺乳动物中,能与酶蛋白形成复合物以发挥酶学活性的有机小分子化合物,目前广泛应用于医药、日化、保健、食品等不同领域。辅酶Q10来源丰富,其中酵母是其工业生产的主要来源之一。广受关注的酵母发酵生产辅酶Q10的提取分离手段不断革新,产量不断增加,处理方式更加环保,应用日渐拓宽。本文就近年来国内外酵母发酵生产辅酶Q10的提取分离方法进行了综述,包括酵母菌种的类型与优化、辅酶Q10提取检测方法、工业生产放大工艺以及与产品质量相关的各个影响因素,并对酵母发酵生产辅酶Q10的前景进行了展望。     

Improvement of maltotriose fermentation by Saccharomyces cerevisiae

AIMS: To enhance the fermentation of maltotriose by industrial Saccharomyces cerevisiae strains. METHODS AND RESULTS: The capability to ferment maltotriose by an industrial yeast strain that uses this sugar aerobically was tested in shake flasks containing rich medium. While the presence of maltose in the medium did not improve maltotriose fermentation, enhanced and constitutive expression of the AGT1 permease not only increased the uptake of maltotriose, but allowed efficient maltotriose fermentation by this strain. Supplementation of the growth medium with 20 mmol magnesium l(-1) also increased maltotriose fermentation. CONCLUSIONS: Over expression of the AGT1 permease and magnesium supplementation improved maltotriose fermentation by an industrial yeast strain that respired but did not ferment this sugar. SIGNIFICANCE AND IMPACT OF THE STUDY: This work contributes to the elucidation of the roles of the AGT1 permease and nutrients in the fermentation of all sugars present in starch hydrolysates, a highly desirable trait for several industrial yeasts.     

透明颤菌血红蛋白的分离纯化与分析检测

透明颤菌血红蛋白(Vitreoscillahemoglobin,VHb)是惟一一种研究得较为透彻的原核生物氧结合蛋白血红蛋白。它支持细胞在微氧条件下进行好氧生长,克服发酵过程中的溶氧限制,因此在需氧微生物发酵工业中具有重要的应用价值。简述了VHb的分离纯化过程,综述了VHb的各种定性检测和定量分析方法,比较了各种检测分析方法的优缺点和适用性。提出利用改进的一氧化碳差光谱法以全细胞悬浮液为对象直接进行VHb的定量分析是发酵工业中应用VHb重组菌株的研究发展方向 。     

蛋白质组学技术在工业发酵梭菌研究中的应用

介绍了目前应用较广泛的蛋白质组学技术的原理、应用及优缺点;总结了发酵工业中常用的梭菌属细菌;重点阐述了蛋白质组学技术在工业发酵梭状芽孢杆菌研究中的应用,为工业发酵菌种的改良和发酵工艺的优化提供理论依据。最后讨论了今后工业发酵菌种蛋白质组学研究的重点和方向。     

工业生物技术专刊序言

以生物催化和生物转化为核心的工业生物技术是实现社会和经济可持续发展的有效手段。本期专刊分别从基因工程、代谢工程与合成生物学、生理工程、发酵工程与生化工程、生物催化与生物转化、生物技术与方法等方面,介绍了我国在工业生物技术领域的最新研究进展。     

Issues in the development of an industrial bioprocess advisory system

The background and motivation for the construction of a fault detection and advisory system for an industrial fermentation process plant are described. Here, the knowledge extracted from the operators (implemented in the form of production rules) is integrated with multivariate data-based methods for fault detection. The industrial benefits arising from this integrated system include: (1) reduced variability, (2) increased mean performance levels, (3) reduced operator-training time and (4) knowledge management in the broader organization.     

2014工业生物技术专刊序言

工业生物技术是解决人类目前面临的资源、能源及环境危机的有效手段。本期专刊结合第七届中国工业生物技术发展高峰论坛,报道了我国工业生物技术领域专家学者在生物信息学、微生物细胞工厂的模拟设计与构建、工业发酵工程、工业酶的改造与应用、高通量筛选方法等领域取得的最新研究进展。