Production of Botrytis cinerea for potential introduction into a vineyard

Botrytis cinerea was produced in solid-phase fermentation, liquid fermentation and on potato dextrose agar. Stored products were evaluated for grape colonization in grape bioassays and in field trials, and for B. cinerea density using colony forming unit analyses and a nucleic-acid-based method. B. cinerea colony forming unit density was significantly correlated to the probability of successful grape colonization in grape bioassays (p-value=0.0002). Solid fermentation products could be stored longer than liquid fermentation and potato dextrose agar products. There was little difference in the rate of grape colonization in laboratory bioassays among solid-phase fermentation, liquid fermentation and plate culture products. Although the initial B. cinerea colonization rate of field grapes was slightly greater on vines treated with solid-phase fermentation and plate culture products compared to vines treated with product from liquid fermentation, there was no significant difference in final colonization between vines treated with solid-phase fermentation, liquid fermentation and plate culture products and untreated vines.     

The fermentation pathways of Escherichia coli

Abstract Under anaerobic conditions and in the absence of alternative electron acceptors Escherichia coli converts sugars to a mixture of products by fermentation. The major soluble products are acetate, ethanol, lactate and formate with smaller amounts of succinate. In addition the gaseous products hydrogen and carbon dioxide are produced in substantial amounts. The pathway generating fermentation products is branched and the flow down each branch is varied in response both the pH of the culture medium and the nature of the fermentation substrate. In particular, the ratio of the various fermentation products is manipulated in order to balance the number of reducing equivalents generated during glycolytic breakdown of the substrate. The enzymes and corresponding genes involved in these fermentation pathways are described. The regulatory responses of these genes and enzymes are known but the details of the underlying regulatory mechanisms are still obscure.     

The fermentation pathways of Escherichia coli

Under anaerobic conditions and in the absence of alternative electron acceptors Escherichia coli converts sugars to a mixture of products by fermentation. The major soluble products are acetate, ethanol, acetate and formate with smaller amounts of succinate. In addition the gaseous products hydrogen and carbon dioxide are produced in substantial amounts. The pathway generating fermentation products is branched and the flow down each branch is varied in response both to the pH of the culture medium and the nature of the fermentation substrate. In particular, the ratio of the various fermentation products is manipulated in order to balance the number of reducing equivalents generated during glycolytic breakdown of the substrate. The enzymes and corresponding genes involved in these fermentation pathways are described. The regulatory responses of these genes and enzymes are known but the details of the underlying regulatory mechanisms are still obscure.     

豆粕营养成分对蝙蝠蛾拟青霉发酵产物的影响

为探索培养基中的豆粕以及制备豆粕的原材料大豆对蝙蝠蛾拟青霉发酵产物的影响,我们比较了不同品种大豆和用其制成的豆粕的主要营养成分含量,包括粗蛋白、粗脂肪、6种微量元素（钙、镁、铜、锌、铁、锰）和总异黄酮（大豆苷、黄豆黄苷、染料木苷、大豆苷元、黄豆黄素、染料木素）,以及豆粕作为培养基对蝙蝠蛾拟青霉发酵产物的生物量和有效成分含量包括腺苷、腺嘌呤、虫草素和麦角甾醇的影响,结果表明大豆中钙和大豆苷与发酵产物中腺苷含量正相关。豆粕中钙、大豆苷、大豆苷元、染料木素与发酵产物中腺苷含量正相关;豆粕中钙、镁、大豆苷、大豆苷元、染料木素、总异黄酮与发酵产物中腺嘌呤含量负相关;豆粕中铁与菌丝体干重值正相关。结果表明,培养基中的豆粕和原料大豆主要营养成分含量对蝙蝠蛾拟青霉发酵产物品质有显著影响。     

By-product inhibition effects on ethanolic fermentation by Saccharomyces cerevisiae

Inhibition by secondary fermentation products may limit the ultimate productivity of new glucose to ethanol fermentation processes. New processes are under development whereby ethanol is selectively removed from the fermenting broth to eliminate ethanol inhibition effects. These processes can concentrate minor secondary products to the point where they become toxic to the yeast. Vacuum fermentation selectively concentrates nonvolatile products in the fermentation broth. Membrane fermentation systems may concentrate large molecules which are sterically blocked from membrane transport. Extractive fermentation systems, employing nonpolar solvents, may concentrate small organic acids. By-product production rates and inhibition levels in continuous fermentation with Saccharomyces cerevisiae have been determined for acetaldehyde, glycerol, formic, lactic, and acetic acids, 1-propanol, 2-methyl-1-butanol, and 2,3-butanediol to assess the potential effects of these by-products on new fermentation processes. Mechanisms are proposed for the various inhibition effects observed.     

食药用菌液体发酵及功能活性成分研究现状与展望

利用食药用菌液体发酵技术可获得品质稳定、产物可控、富含多种有效营养和活性成分的功能性原料。本文系统总结了食药用菌液体发酵技术的研究现状和瓶颈,以及食药用菌液体发酵产物中的主要成分和功效,并与栽培子实体进行了比较。通过对食药用菌液体发酵技术瓶颈突破的展望,为食药用菌液体发酵产物的进一步应用提供参考。     

微生物发酵青蒿叶和叶渣的研究

为扩大青蒿原料的应用途径,延伸青蒿产业链,对青蒿叶和叶渣进行发酵研究.拟开发可用于动物保健的青蒿来源的产品.采用微生物发酵青蒿及青蒿叶渣,检测枯草芽孢杆菌、酿酒酵母菌、植物乳杆菌等菌株发酵青蒿叶和叶渣后其粗蛋白、粗脂肪、粗纤维素以及青蒿素、青蒿乙素、双氢青蒿酸、青蒿酸含量变化.青蒿叶发酵产物及功效成分含量与对照组比较,...     

Redox potential control and applications in microaerobic and anaerobic fermentations

Many fermentation products are produced under microaerobic or anaerobic conditions, in which oxygen is undetectable by dissolved oxygen probe, presenting a challenge for process monitoring and control. Extracellular redox potentials that can be detected conveniently affect intracellular redox homeostasis and metabolism, and consequently control profiles of fermentation products, which provide an alternative for monitoring and control of these fermentation processes. This article reviews updated progress in the impact of redox potentials on gene expression, protein biosynthesis and metabolism as well as redox potential control strategies for more efficient production of fermentation products, taking ethanol fermentation by the yeast Saccharomyces under microaerobic conditions and butanol production by the bacterium Clostridium under anaerobic conditions as examples.     

Comparison of solid-state and submerged-state fermentation for the bioprocessing of switchgrass to ethanol and acetate by Clostridium phytofermentans

The conversion of sustainable energy crops using microbiological fermentation to biofuels and bioproducts typically uses submerged-state processes. Alternatively, solid-state fermentation processes have several advantages when compared to the typical submerged-state processes. This study compares the use of solid-state versus submerged-state fermentation using the mesophilic anaerobic bacterium Clostridium phytofermentans in the conversion of switchgrass to the end products of ethanol, acetate, and hydrogen. A shift in the ratio of metabolic products towards more acetate and hydrogen production than ethanol production was observed when C. phytofermentans was grown under solid-state conditions as compared to submerged-state conditions. Results indicated that the end product concentrations (in millimolar) obtained using solid-state fermentation were higher than using submerged-state fermentation. In contrast, the total fermentation products (in weight of product per weight of carbohydrates consumed) and switchgrass conversion were higher for submerged-state fermentation. The conversion of xylan was greater than glucan conversion under both fermentation conditions. An initial pH of 7 and moisture content of 80 % resulted in maximum end products formation. Scanning electron microscopy study showed the presence of biofilm formed by C. phytofermentans growing on switchgrass under submerged-state fermentation whereas bacterial cells attached to surface and no apparent biofilm was observed when grown under solid-state fermentation. To our knowledge, this is the first study reporting consolidated bioprocessing of a lignocellulosic substrate by a mesophilic anaerobic bacterium under solid-state fermentation conditions.     

Non-sterile fermentations for the economical biochemical conversion of renewable feedstocks

Heavy reliance on petroleum-based products drives continuous exploitation of fossil fuels, and results in serious environmental and climate problems. To address such an issue, there is a shift from petroleum sources to renewable ones. Biochemical conversion via fermentation is a primary platform for converting renewable sources to biofuels and bulk chemicals. In order to provide cost-competitive alternatives, it is imperative to develop efficient, cost-saving, and robust fermentation processes. Non-sterile fermentation offers several benefits compared to sterile fermentation, including elimination of sterility, reduced maintenance requirements, relatively simple bioreactor design, and simplified operation. Thus, cost effectiveness of non-sterile fermentation makes it a practical platform for low cost, large volume production of biofuels and bulk chemicals. Many approaches have been developed to conduct non-sterile fermentation without sacrificing the yields and productivities of fermentation products. This review focuses on the strategies for conducting non-sterile fermentation. The challenges facing non-sterile fermentation are also discussed.     

传统发酵肉制品中微生物菌群对风味形成的研究进展

我国传统发酵肉制品种类丰富、风味独特。本文主要介绍参与肉制品发酵的微生物,从蛋白质、脂质和碳水化合物代谢途径的角度概述微生物对发酵肉制品呈香物质形成的作用机制,以及发酵过程中微生物的演替与风味变化的关系。     

Excretion of fermentation products in dark and anaerobically incubated cyanobacteria

An arbitrarily chosen selection of 37 cyanobacterial strains of the Oldenburg culture collection were tested for their ability of fermentation and secretion of fermentation products. In all examined strains at least one fermentation product could be detected. For the most part fermentation products were only shed in traces. Thus, for a large part of the investigated strains fermentation does not seem to be a sufficient metabolism to survive dark and anaerobic periods. Only five strains secreted remarkable amounts of products. Glycollate was mostly found in combination with formate and/or traces of oxalate. Lactate, ethanol and acetate were found in combination or single. Most of those strains sheding high amounts of glycollate and formate, did not show a remarkable lactate, ethanol or acetate excretion; those excreting high amounts of lactate, ethanol or acetate produced only minor volumes of glycollate and formate. It was not possible to find similar fermentation patterns by comparing fermentation of species belonging to the same family. Organisms fermenting or not fermenting could be found among marine, brackish and freshwater cyanobacteria. Fermentation, therefore seems to be a unique, and likely old capability among cyanobacteria, which was partly lost during evolution.     

Lessons from the cow: What the ruminant animal can teach us about consolidated bioprocessing of cellulosic biomass

Consolidated bioprocessing (CBP) of cellulosic biomass is a promising source of ethanol. This process uses anaerobic bacteria, their own cellulolytic enzymes and fermentation pathways that convert the products of cellulose hydrolysis to ethanol in a single reactor. However, the engineering and economics of the process remain questionable. The ruminal fermentation is a very highly developed natural cellulose-degrading system. We propose that breakthroughs developed by cattle and other ruminant animals in cellulosic biomass conversion can guide future improvements in engineered CBP systems. These breakthroughs include, among others, an elegant and effective physical pretreatment; operation at high solids loading under non-aseptic conditions; minimal nutrient requirements beyond the plant biomass itself; efficient fermentation of nearly all plant components; efficient recovery of primary fermentation end-products; and production of useful co-products. Ruminal fermentation does not produce significant amounts of ethanol, but it produces volatile fatty acids and methane at a rapid rate. Because these alternative products have a high energy content, efforts should be made to recover these products and convert them to other organic compounds, particularly transportation fuels.     

生防链霉菌ZM-16的发酵产物生物活性及其微波诱变育种

【目的】链霉菌ZM-16对多种细菌有良好的抑菌作用,其发酵产物的主要活性物质为放线菌素D。本研究旨在进一步探讨其抗真菌活性,并通过诱变育种的方法对菌种进行改良,以提高活性物质的产量,从而为其在植物病害生物防治领域的实践应用奠定基础。【方法】利用液体发酵的方法获取活性产物并对其进行粗提取;利用抑菌圈法检测菌株发酵产物对11种植物病原真菌的抑制作用;通过微波处理并利用抗生素抗性筛选的方法对菌株进行诱变育种。【结果】粗提液对11种植物病原真菌均具有抑菌效果,最为明显的3种病菌分别是苹果炭疽病菌、油菜菌核病菌和禾谷镰刀病菌;经微波诱变筛选到了一株耐利福平突变株,其放线菌素D的产量提高了36.75%;传代研究表明其经过10代选育,遗传稳定性较好。【结论】链霉菌ZM-16的发酵产物具有良好的抗植物病原真菌的活性,经过育种后其活性产物产量也有所提高,因此具有较高的实际应用价值。     

灵芝真菌液体发酵及其产物应用的研究进展

灵芝作为一种白腐真菌,同时也是珍稀的食药用真菌,富含多种生物活性成分。液体发酵技术生产周期短、效率高、产量大、品质稳定,是开发利用灵芝资源的重要途径。近年来,灵芝属真菌菌丝体液体发酵技术的开发与应用取得了较大进展。本文对灵芝属真菌液体发酵产物的主要活性成分及其药用效果、液体发酵工艺优化和发酵产物的应用进行综述,并对本领域的未来进行展望。     

Biological activity in traditional Alaska pollack sikhae during low temperature fermentation

Biological activity was examined on Alaska pollack sikhae produced with 4 treatments (by irradiating at 5 or 10 kGy, or by adding either 0.1 or 0.3% of chitooligosaccharide), compared with control (2-step fermentation only) during fermentation at -2 degrees C. The extracts (500 ppm level) of sikhae had antimicrobial activities against 4 different strains of food poisoning bacteria such as Staphy. aureus, B. subtilis, B. cereus, and L. monocytogenes. Antioxidative activity (EDA(50), 11.55 mg/mL) in control group increased with time up to 60 days of fermentation but decreased thereafter, while those levels in other products were kept within 10.60-18.30 mg/mL ranges during fermentation. Inhibitory activity of angiotensin-I converting enzyme (ACE) (IC(50), 1.51-2.89 mg/mL) in all products was observed during fermentation except at 0 day. Inhibitory activity of xanthine oxidase (XO) (IC(50), 0.65-0.87 mg/mL) in all products also increased with time up to 30 days of fermentation. Without irradiating or adding of chitooligosaccharide, Alaska pollack sikhae showing biological activities was enough by 2-step fermentation and storage at -2 degrees C only.     

End-product inhibition in anaerobic fermentations

The accumulation of products in a fermentation broth inhibits the growth of producer organisms and decreases the fermentor's productivity. Studies of bacterial physiology have provided new insights into the mechanisms of end-product inhibition and these may lead to reduced manufacturing costs for fermentation products such as ethanol, butanol, acetone and lactic acid.     

Lactic-acid fermentation as a low-cost means of food preservation in tropical countries

Abstract The range of traditional lactic-acid-fermented foods in tropical countries is briefly reviewed. Recent studies on the lactic acid fermentation of fish and cassava products are described. Lactic-acid-fermented fish products may offer considerable scope for the development of new food products and for the use of under-utilised fish species. Lactic-acid-fermented fish products are common in parts of Asia; methods to improve the product and shelf-life quality, to reduce microbial risks and to accelerate the process are described. This work is based on fish/salt/carbohydrate model systems. The nutritional aspects of cassava fermentation are discussed with respect to factors involved in determining residual cyanide levels; the possible anti-nutritional rôle of condensed tannins is mentioned. The increasing consumption of meat products in tropical countries emphasises the need for a preservation method that does not depend on refrigeration. The possible production of sausage ingredients preserved by lactic acid fermentation, and the associated research needs are described.     

Butanol production from cellulosic substrates by sequential co-culture ofClostridium thermocellum andC.acetobutylicum

A sequential co-culture approach was investigated for the conversion of lignocellulosic substrates to fuels and chemicals. Growth ofClostridium acetobutylicum on solka floc (or a mixture of solka floc and aspenwood xylan), in co-culture withC.thermocellum, resulted in the efficient utilization of all the hydrolysis products derived from the lignocellulosic substrates. This co-culture approach resulted in a 1.7–2.6 fold increase in the total fermentation products formed. The majority of the fermentation products were acids and not solvents, however the solventogenesis step could be induced by the addition of butyric acid to the fermentation medium.     

Eremomycin的发酵条件优化及发酵产物的分离纯化

研究确定Nocardia orientalis NRRL18098发酵生产eremomycin的最佳工艺条件,以及对发酵产物进行分离纯化并得到eremomycin的纯品。通过正交设计方法优化发酵培养基的组成。采用树脂吸附、中压液相色谱技术相结合的方法对发酵产物进行分离纯化。在优化条件下,eremomycin的摇瓶发酵单位达115 mg/L,提高了63.5%,并采用树脂吸附和中压液相色谱相结合的方法能有效地将eremomycin从发酵液中分离出来,制备获得eremomycin精制品。