衣康酸发酵研究进展

衣康酸作为一种平台化合物,可被各行业广泛用于多种高附加值产品的生产,其更是具有替代传统石油基原料的潜力,在工业生产中有着重要地位与应用前景.目前,衣康酸主要由土曲霉深层好氧发酵生产,碳源、氮源、磷酸盐、金属离子、溶解氧、pH、温度等条件对其产量影响显著.在衣康酸生产中,原料成本高是阻碍其市场进一步扩大与发展的重要因素....     

Natural cashew apple juice as fermentation medium for biosurfactant production by Acinetobacter calcoaceticus

The success of biosurfactant production depends on the development of cheaper processes based on the use of low cost raw materials, which account for 10–30% of the overall process cost. In Brazil, the cashew apple agroindustry plays an outstanding role in the local economy. However, only a small part of the pseudofruit produced is used industrially and the amount wasted (about 94%) presents high potential as fermentation media, since it is rich in carbohydrate, fibers, vitamins and minerals salts. In this work, the performance of cashew apple juice (CAJ) as a complex medium for Acinetobacter calcoaceticus growth and production of biosurfactant was investigated. The microorganism was able to grow and to produce biosurfactant on a defined culture medium and on CAJ, reducing the surface tension of both media. The biosurfactant also achieved a maximum emulsion index of 80% for kerosene, when defined medium was used.     

Fumaric acid production by fermentation

The potential of fumaric acid as a raw material in the polymer industry and the increment of cost of petroleum-based fumaric acid raises interest in fermentation processes for production of this compound from renewable resources. Although the chemical process yields 112% w/w fumaric acid from maleic anhydride and the fermentation process yields only 85% w/w from glucose, the latter raw material is three times cheaper. Besides, the fermentation fixes CO₂. Production of fumaric acid by Rhizopus species and the involved metabolic pathways are reviewed. Submerged fermentation systems coupled with product recovery techniques seem to have achieved economically attractive yields and productivities. Future prospects for improvement of fumaric acid production include metabolic engineering approaches to achieve low pH fermentations.     

Industrial chemicals from fermentation

This paper examines the potential for carbohydrate fermentation as an alternative process technology for bulk organic chemicals. Major limitations restricting the broadening of scope for fermentation chemicals are identified. These involve the high process energy requirements in pretreating abundant cellulosic feedstocks, low overall conversion, low weight yield and limited product applications of directly biosynthesized fermentation chemicals. The new development directions for chemicals derived directly and indirectly from carbohydrate fermentation are reviewed. The significance of their potential impact on the evolving organic chemical industry is projected.     

Protein,amino acid and mineral composition of some edible insects from Thailand

This paper focuses on the nutritional profiles of four edible insects from Thailand: the Bombay locust, scarab beetle, house cricket, and mulberry silkworm.The insects were ‘high’ in protein ranging from 27 g to 54 g/100 g edible portion in fresh weight basis, however, only the silkworm met the FAO/WHO requirements of 40% essential amino acids and 0.6 ratio of essential to non-essential amino acids. Tryptophan is the limiting amino acid in the locust and cricket, lysine in the scarab beetle, and leucine in the silkworm.The locust is a ‘source’ of iron and is ‘high’ in zinc, while the scarab beetle is a ‘source’ of magnesium and is ‘high’ in iron and zinc. The cricket bought from the street is a ‘source’ of iron and magnesium and is ‘high’ in zinc, while the cricket from the supermarket is a ‘source’ of calcium (the only one among the insect samples) and is ‘high’ in iron, magnesium and zinc. And lastly, the silkworm, regardless of where it was purchased, is a ‘source’ of iron and is ‘high’ in magnesium and zinc. The arsenic, cadmium, lead and mercury content of all the insect samples were well below the maximum values and are deemed safe for consumption as either feed material or complete feed.Edible insects can contribute to people's nutrient requirements and should be sustainably utilized. Aside from direct consumption, there is a huge potential for using the insects as raw material and fortificant in food processing.     

蓝细菌固碳合成乳酸技术的发展与展望

乳酸是一种重要的工业化学品,被广泛应用于各个行业。近年来,随着聚乳酸(PLA)市场的兴起,乳酸原料的需求也在不断增加。糖基异养生产乳酸所带来的高昂成本与市场需求的矛盾吸引着研究人员积极寻找其他有利的解决方案。蓝细菌光合固碳生产乳酸是一种潜力巨大的新型原料供应策略,基于光合自养的细胞工厂,可以在单一平台上以太阳能为驱动力,从二氧化碳中直接生产出高光学纯度的乳酸。该方法原料廉价易得、过程简单可控、产物明确且易分离,同时达到节能减排和高附加值产品生产的双重效果,具有重要的研究与应用价值。文中回顾了蓝细菌固碳产乳酸技术的发展历程,从代谢基础、代谢工程策略、代谢动力学分析与技术应用等方面,梳理其研究进展和所遇到的技术难点,并对该技术的未来进行展望。     

Tracing and control of raw materials sourcing for vaccine manufacturers

The control of the raw materials used to manufacture vaccines is mandatory; therefore, a very clear process must be in place to guarantee that raw materials are traced. Those who make products or supplies used in vaccine manufacture (suppliers of culture media, diagnostic tests, etc.) must apply quality systems proving that they adhere to certain standards. ISO certification, Good Manufacturing Practices for production sites and the registration of culture media with a ‘Certificate of Suitability’ from the European Directorate for the Quality of Medicines and Healthcare are reliable quality systems pertaining to vaccine production. Suppliers must assure that each lot of raw materials used in a product that will be used in vaccine manufacture adheres to the level of safety and traceability required. Incoming materials must be controlled in a single ‘Enterprise Resource Planning’ system which is used to document important information, such as the assignment of lot number, expiration date, etc. Ingredients for culture media in particular must conform to certain specifications. The specifications that need to be checked vary according to the ingredient, based on the level of risk.The way a raw material is produced is also important, and any aspect relative to cross-contamination, such as the sanitary measures used in producing and storing the raw material must be checked as well. In addition, suppliers can reduce the risk of viral contamination of raw materials by avoiding purchases in countries where a relevant outbreak is currently declared.     

Growth,salinity tolerance and extracellular carbohydrate yield of Prasinocladus marinus (Cienk.) Waern (class prasinophyceae)

Growth of Prasinocladus marinus (Cienk.) Waern was maximal in media of 35‰ salinity, showing a five-fold increase over a 7-day period. At lower salinities (10–27.5‰) growth varied between 55–90% and at 45‰ was 85% of that in ‘normal’ sea water. Yield of extracellular carbohydrate was higher than in ‘normal’ sea water in lowered salinities and at 45‰ over a 42-day period. Larger quantities of extracellular carbohydrate were obtained at all stages of growth in media of 15‰, compared with those of 35‰ and 45‰. Whilst growth forms were markedly different at low salinities, DNA measurements indicated that similar quantities of cell material were present. Mannitol and glucose were the principal carbohydrates identified in intracellular material, and glucose in the extracellular products. Chloroplast pigment synthesis appears unaffected by growth at 15‰, 35‰, and 45‰.     

Towards industrial pentose-fermenting yeast strains

Production of bioethanol from forest and agricultural products requires a fermenting organism that converts all types of sugars in the raw material to ethanol in high yield and with a high rate. This review summarizes recent research aiming at developing industrial strains of Saccharomyces cerevisiae with the ability to ferment all lignocellulose-derived sugars. The properties required from the industrial yeast strains are discussed in relation to four benchmarks: (1) process water economy, (2) inhibitor tolerance, (3) ethanol yield, and (4) specific ethanol productivity. Of particular importance is the tolerance of the fermenting organism to fermentation inhibitors formed during fractionation/pretreatment and hydrolysis of the raw material, which necessitates the use of robust industrial strain background. While numerous metabolic engineering strategies have been developed in laboratory yeast strains, only a few approaches have been realized in industrial strains. The fermentation performance of the existing industrial pentose-fermenting S. cerevisiae strains in lignocellulose hydrolysate is reviewed. Ethanol yields of more than 0.4 g ethanol/g sugar have been achieved with several xylose-fermenting industrial strains such as TMB 3400, TMB 3006, and 424A(LNF-ST), carrying the heterologous xylose utilization pathway consisting of xylose reductase and xylitol dehydrogenase, which demonstrates the potential of pentose fermentation in improving lignocellulosic ethanol production.     

L-lactic acid production by Lactobacillus casei fermentation with corn steep liquor-supplemented acid-hydrolysate of soybean meal

Batch and fed-batch fermentation studies were performed to evaluate the potential of corn steep liquor (CSL)-supplemented acid-hydrolysate of soybean meal (AHSM) as an alternative to yeast extract (YE) for the production of L-lactic acid by Lactobacillus casei LA-04-1. The CSL-supplemented AHSM gave an outstanding result in supporting L-lactic acid production from glucose. In the exponential fed-batch fermentation, the concentration, yield and productivity of L-lactic acid were 162.5 g/L, 89.7% and 1.69 g/L per h, respectively, which were lower than those with 20 g/L YE (180 g/L, 90.3%, 2.14 g/L per h) after 96 h of fermentation. However, the raw material cost of the nitrogen resource was estimated as only 25% of that using the YE.     

Increased attractiveness of honeybee hive product volatiles to adult small hive beetle,Aethina tumida,resulting from small hive beetle larval infestation

The small hive beetle, Aethina tumida Murray (Coleoptera: Nitidulidae), is a recent but significant pest of honeybee [Apis mellifera L. (Hymenoptera: Apidae)] hives in various regions throughout the world, including Eastern Australia. The larval stage of this beetle damages hives when they feed on brood, pollen, and honeycomb, leaving behind fermented wastes. In cases of extreme damage, hives collapse and are turned to an odorous mass of larvae in fermenting hive products. The yeast Kodamaea ohmeri (Etchells & Bell) Yamada et al. (Ascomycota) has been consistently isolated from the fermenting material as well as each life stage of this beetle. Various studies have noted that the small hive beetle is attracted to volatiles from hive products and those of the yeast K. ohmeri, although earlier studies have not used naturally occurring hive products as their source of fermentation. This study investigated changes through time in the attractiveness of natural honeybee hive products to the small hive beetle as the hive products were altered by the action of beetle larvae and fermentation by K. ohmeri. We used gas chromatography‐mass spectrometry and choice‐test behavioural assays to investigate these changes using products sampled from three apiaries. Attractiveness of the fermenting hive products (‘slime’) increased as fermentation progressed, and volatile profiles became more complex. Fermenting hive products remained extremely attractive for more than 30 days, significantly longer than previous reports. These results have strong implications for the development of an external attractant trap to assist in the management of this invasive pest.     

Citric Acid Fermentation and the Effects of Temperature

The temperature of the fermentation media heavily affects yields as well as rates of citric acid fermentations. At 26–28 °C, more than 40% of the available carbohydrate raw material is wasted, apparently through the respiratory activity of the fungus. At 30–32 °C, these losses are decreased to about 10%. The results thus emphasise the economic importance of adequate temperature control in industrial citric acid fermentation.     

Flexible biorefinery for producing fermentation sugars, lignin and pulp from corn stover

A new biorefining process is presented that embodies green processing and sustainable development. In the spirit of a true biorefinery, the objective is to convert agricultural residues and other biomass feedstocks into value-added products such as fuel ethanol, dissolving pulp, and lignin for resin production. The continuous biomass fractionation process yields a liquid stream rich in hemicellulosic sugars, a lignin-rich liquid stream, and a solid cellulose stream. This paper generally discusses potential applications of the three streams and specifically provides results on the evaluation of the cellulose stream from corn stover as a source of fermentation sugars and specialty pulp. Enzymatic hydrolysis of this relatively pure cellulose stream requires significantly lower enzyme loadings because of minimal enzyme deactivation from nonspecific binding to lignin. A correlation was shown to exist between lignin removal efficiency and enzymatic digestibility. The cellulose produced was also demonstrated to be a suitable replacement for hardwood pulp, especially in the top ply of a linerboard. Also, the relatively pure nature of the cellulose renders it suitable as raw material for making dissolving pulp. This pulping approach has significantly smaller environmental footprint compared to the industry-standard kraft process because no sulfur- or chlorine-containing compounds are used. Although this option needs some minimal post-processing, it produces a higher value commodity than ethanol and, unlike ethanol, does not need extensive processing such as hydrolysis or fermentation. Potential use of low-molecular weight lignin as a raw material for wood adhesive production is discussed as well as its use as cement and feed binder. As a baseline application the hemicellulosic sugars captured in the hydrolyzate liquor can be used to produce ethanol, but potential utilization of xylose for xylitol fermentation is also feasible. Markets and values of these applications are juxtaposed with market penetration and saturation.     

Bioethanol: Experiences from running plants,optimization and prospects

In the past decades, the agro-industry in Europe has made a tremendous move from more regional to globally operating food groups processing a variety of different crops to agrochemicals, e.g. to carbohydrates such as sugars, starches and inulin. Moreover, these agrochemicals are feedstocks for a variety of further processed products. Biotechnology plays a central role in these material transformations. Besides a considerable number of developments using enzyme technology as ‘chemical’ catalysts, for example for the production of Palatinose? (isomaltulose), isomalt, and oligofructosides or special inulins, fermentations are starting to become an important tool, too. When the EU made the move towards bio-fuels, European agro-industry decided to become a major player in this field. For bio-ethanol production, besides raw material the factors with the highest impact on overall costs are energy consumption and yield. To optimize both, innovative developments were successfully established for different process steps, including fermentation and enzymatic hydrolysis of starch and other bio-polymers. Further optimization of yeasts, for example by using gene modification technology, is possible. Besides specific energy saving techniques like multi effect evaporation and distillation, enzyme technology has made a great contribution to reduction in overall energy consumption. For further energy savings, improved enzymes are necessary and should be developed.     

Variation of Chemical Constituents and Antiradical Capacity of Nine Ferulago angulata Populations from Iran

The present study was designed to assess the influence of geographical factors on essential oil (EO) composition, along with antiradical potential and phytochemical contents of Ferulago angulata (Schltdl .) Boiss (Apiaceae) extracts for the first time. The aerial parts were hydrodistilled by Clevenger apparatus and subjected to gas chromatography coupled with flame ionization detector (GC/FID) and mass spectroscopy (GC/MS). The EO yields were significantly different from populations ‘Mongar’ (south‐slope, 3000 m) with 1.34±0.06 % and ‘Male‐Amiri’ (north slope, 2600 m) with 0.18±0.05 % of total oil. Thirty‐nine compounds were identified from the EOs of nine populations. α‐Pinene was the predominant component ranging from 20.84 to 49.06 % in ‘Gandomkar’ (north‐slope, 2500 m) and ‘Mongar’ (3000 m), respectively. The methanolic extract of ‘Mongar’ (north‐slope at 2500 m) possessed the highest total phenolic contents. Also, this population logically exhibited potent antiradical activity using both 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) and oxygen radical absorbance capacity (ORAC) assays with EC₅₀ of 42.07±4.12 μg/mL and 8.34±0.21 mmol Trolox® equivalents/g, respectively. Due to its moderate free‐radical scavenging potential and high α‐pinene content, the population ‘Mongar’ might be considered as a perspective raw material in food and phytopharmaceutical industries.     

Fermentation of pentose sugars to ethanol and other neutral products by microorganisms

The current and projected shortage of petroleum and natural gas has led to renewed interest in processes for the microbial conversion of renewable biomass resources to liquid and gaseous fuels. Pentose sugars represent a significant fraction of the total fermentable carbohydrate content of biomass. A number of biochemical pathways are known for the conversion of pentose to ethanol and other neutral products. Beside ethanol, potential neutral fermentation products include 2,3-butanediol, acetone, isopropanol, butanol and hydrogen. Other products include carbon dioxide and organic acids. Specific ethanol-producing fermentations are reviewed, and future directions for research and development are suggested.     

Ethanol fermentation and potential.

Ethyl alcohol is one of the United States and world's major chemicals. Beverage alcohol in the United States must be prepared from cereal grains or other natural products. The U.S. industrial alcohol market has remained relatively stable for several years at approximately 300 million gallons annually. Most of this has been produced synthetically from petroleum raw material (gas and oil). These raw materials are experiencing major price increases and are in short supply. The production of ethyl alcohol from cereal grains and cellulosic raw materials by fermentation is technically feasible and has been proven. Alcohol produced from all such materials is equal to synthetic alcohol in quality and performance. Competitive economics have controlled the basic raw materials used. The major potential new ethyl alcohol market is as a component of automobile fuels. A 10% alcohol-gasoline blend in the United States would annually require over 10 billion gallons of anhydrous alcohol. Use of alcohol for this purpose is technically feasible. However, alcohol has not been economically competitive to date.     

植物天然产物微生物重组合成研究进展

植物天然产物是小分子药物、营养品、化妆品、香精香料等的主要来源之一,在国民经济中发挥重要的作用。目前植物天然产物主要依赖于植物提取,这种生产方式占用耕地、生长周期长,而且植物活性成分往往含量低、生产成本高。通过解析植物天然产物生物合成途径,在微生物细胞中重构,创建细胞工厂,实现利用可再生原料发酵合成,为植物天然产物的供给提供了新的路线。本文重点介绍了中国科学院天津工业生物技术研究所在萜类、黄酮类、苯丙素类等重要类型植物天然产物微生物重组合成方面的研究进展,简要探讨了当前研究面临的挑战及未来前景。     

Filtration, haze and foam characteristics of fermented wort mediated by yeast strain

AIMS: To investigate the influence of the choice of yeast strain on the haze, shelf life, filterability and foam quality characteristics of fermented products. METHODS AND RESULTS: Twelve strains were used to ferment a chemically defined wort and hopped ale or stout wort. Fermented products were assessed for foam using the Rudin apparatus, and filterability and haze characteristics using the European Brewing Convention methods, to reveal differences in these parameters as a consequence of the choice of yeast strain and growth medium. CONCLUSIONS: Under the conditions used, the choice of strain of Saccharomyces cerevisiae effecting the primary fermentation has an impact on all of the parameters investigated, most notably when the fermentation medium is devoid of macromolecular material. SIGNIFICANCE AND IMPACT OF THE STUDY: The filtration of fermented products has a large cost implication for many brewers and wine makers, and the haze of the resulting filtrate is a key quality criterion. Also of importance to the quality of beer and some wines is the foaming and head retention of these beverages. The foam characteristics, filterability and potential for haze formation in a fermented product have long been known to be dependant on the raw materials used, as well as other production parameters. The choice of Saccharomyces cerevisiae strain used to ferment has itself been shown here to influence these parameters.