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1.
The method of disks in combination with thin-layer chromatography and spectrophotometry was used for a comparative evaluation of the efficiency of different methods of fixing and fermentation of medicinal plants (leaves). Medicinal plant species capable of synthesizing alkaloids of various structural types (isoquinoline derivatives including benzophenanthridines, bisbenzylisoquinoline, quaternary protoberberines, and aporphines, as well as steroid and diterpene alkaloids) were used. The methods of fixing and fermentation were shown to exert a substantial effect on both the qualitative and quantitative composition of alkaloids. This difference in the alkaloid composition was found to represent the superposition of three independent and, to a large extent, opposite processes: catabolism of alkaloids, interaction of alkaloids with each other, and resynthesis from primary precursors. The use of different methods of fixing and fermentation provides activation or inhibition of these processes, thereby making it possible to carry out target-oriented correction of the alkaloid composition of the medicinal plants studied. 相似文献
2.
The method of disks in combination with thin-layer chromatography and spectrophotometry was used for a comparative evaluation of the efficiency of different methods of fixing and fermentation of medicinal plants (leaves). Medicinal plant species capable of synthesizing alkaloids of various structural types (isoquinoline derivatives including benzophenanthridines, bisbenzylisoquinoline, quaternary protoberberines, and aporphines, as well as steroid and diterpene alkaloids) were used. The methods of fixing and fermentation were shown to exert a substantial effect on both the qualitative and quantitative composition of alkaloids. This difference in the alkaloid composition was found to represent the superposition of three independent and, to a large extent, opposite processes: catabolism of alkaloids, interaction of alkaloids with each other, and resynthesis from primary precursors. The use of different methods of fixing and fermentation provides activation or inhibition of these processes, thereby making it possible to carry out target-oriented correction of the alkaloid composition of the medicinal plants studied. 相似文献
3.
2D spectrofluorometry produces a large volume of spectral data during fermentation processes with recombinant E. coli, which can be analyzed using chemometric methods such as principal component analysis (PCA), principal component regression (PCR) and partial least square regression (PLS). An analysis of the spectral data by PCA results in scores and loadings that are not only visualized in the score-loading plots but are also used to monitor the fermentation processes on-line. The score plots provided useful qualitative information on four fermentation processes for the production of extracellular 5-aminolevulinic acid (ALA). Two chemometric models (PCR and PLS) were used to examine the correlation between the 2D fluorescence spectra and a few parameters of the fermentation processes. The results showed that PLS had slightly better calibration and prediction performance than PCR. 相似文献
4.
Lignocellulose might become an important feedstock for the future development of the biobased economy. Although up to 75 % of the lignocellulose dry weight consists of sugar, it is present in a polymerized state and cannot be used directly in most fermentation processes for the production of chemicals and fuels. Several methods have been developed to depolymerize the sugars present in lignocellulose, making the sugars available for fermentation. In this review, we describe five different pretreatment methods and their effect on the sugar and non-sugar fraction of lignocellulose. For several pretreatment methods and different types of lignocellulosic biomass, an overview is given of by-products formed. Most unwanted by-products present after pretreatment are dehydrated sugar monomers (furans), degraded lignin polymers (phenols) and small organic acids. Qualitative and quantitative effects of these by-products on fermentation processes have been studied. We conclude this review by giving an overview of techniques and methods to decrease inhibitory effects of unwanted by-products. 相似文献
5.
Biofuel research and development roadmap is currently underway in several countries and is expected to pave a way for the establishment of a viable renewable energy sector that can compete with petroleum-based fuels. Ethanol fermentation has garnered increasing attention amongst various stakeholders (industries, governments, and academia) due to its economic and environmental merits. However, microbial contamination continues to be one of the major barriers in ethanologenic processes, resulting in low ethanol yields and thereby translating into economic losses. To this end, technological innovations geared towards effective elimination of microbial contamination are constantly being developed. This review explores and discusses the fermentation conditions that facilitate the growth of undesired microorganisms during ethanol fermentation processes. It highlights the methods that are currently used in biorefineries as well as innovative and advanced biotechnological methods currently being evaluated as viable alternative strategies to control or eliminate microbial contaminants in ethanol fermentations. These methods have the potential to minimize or control the contamination problem and could pave a way for the development of an efficient biofuel sector. 相似文献
6.
Succinic acid is of high interest as bio-feedstock for the chemical industry. It is a precursor for a variety of many other chemicals, e.g. 1,4-butandiol, tetrahydrofuran, biodegradable polymers and fumaric acid. Besides optimized production strains and fermentation processes it is indispensable to develop cost-saving and energy-effective downstream processes to compete with the current petrochemical production process. Various methods such as precipitation, sorption and ion exchange, electrodialysis, and liquid–liquid extraction have been investigated for the recovery of succinic acid from fermentation broth and are reviewed critically here. 相似文献
7.
The modelling of winemaking processes, to predict as far ahead as possible the fermentation performance, is necessary for enhanced supervision and to enable appropriate corrective action to be taken to remedy incorrect fermentation before it is too late. In this paper, we briefly present two heuristic modelling methods—the Group Method of Data Handling (GMDH) and Neural Networks (NN)—which can be used to obtain unstructured models. The identification and prediction performances of the models obtained with these two methods are compared with respect to the alcoholic fermentation rate (dCO 2/d t) at five prediction horizons and for four fermentations. It is shown that predictive models obtained with neural network methodology are more accurate than those obtained with GMDH. On the other hand, GMDH models are more versatile when used for the prediction of the fermentation rate of a different fermentation than the one used in the learning process. 相似文献
8.
Two rapid methods for on-line protein determination useful for control purposes in the automation of biotechnological processes such as fermentation and downstream processing are described. Both methods are derived from colorimetric laboratory biuret and Bradford protein assays adapted to a flow injection analyser. 相似文献
10.
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 。 相似文献
11.
The early detection of microbial contamination is crucial to avoid process failure and costly delays in fermentation industries. However, traditional detection methods such as plate counting and microscopy are labor-intensive, insensitive, and time-consuming. Modern techniques that can detect microbial contamination rapidly and cost-effectively are therefore sought. In the present study, we propose gas chromatography-mass spectrometry (GC-MS)-based metabolic footprint analysis as a rapid and reliable method for the detection of microbial contamination in fermentation processes. Our metabolic footprint analysis detected statistically significant differences in metabolite profiles of axenic and contaminated batch cultures of microalgae as early as 3 h after contamination was introduced, while classical detection methods could detect contamination only after 24 h. The data were analyzed by discriminant function analysis and were validated by leave-one-out cross-validation. We obtained a 97% success rate in correctly classifying samples coming from contaminated or axenic cultures. Therefore, metabolic footprint analysis combined with discriminant function analysis presents a rapid and cost-effective approach to monitor microbial contamination in industrial fermentation processes. 相似文献
12.
Linear relations among net conversion rates of primary metabolites in fermentation processes can be determined by using the macroscopic or pathway balancing methods. It is shown that the process observability can be improved by incorporating both the abiotic proton balance and the pH control reagent addition rate measurement into the balancing methods. (c) 1996 John Wiley & Sons, Inc. 相似文献
13.
AIMS: Little information exists regarding the microbiology of two traditional Maori food preparation processes which may involve fermentations. Preliminary microbiological and chemical analyses were carried out on these two foods in order to identify the fermentations involved (if any). METHODS AND RESULTS: Testing was carried out on freshly-prepared foods and on those that had been processed and stored. Kina (sea urchins, Evechinus chloroticus) are harvested and then stored either under fresh water or buried underground. The most frequently-occurring process appeared to be an alkaline fermentation. Large numbers of Clostridium perfringens were detected in one set of samples prepared outside of the traditional season, but this was the only pathogen detected. In Kina stored in buried plastic bottles during the traditionally-accepted time of the year, bacterial numbers decreased. Tiroi is prepared from mussels and Puha (sow thistle, Sonchos asper) that have been cooked to some degree, combined and stored. Of three methods used to prepare and store Tiroi, the results for one indicated the possible involvement of a lactic acid fermentation, but the other two methods were effectively only cooking and bottling processes. CONCLUSIONS: In the case of Kina, the use of an alkaline fermentation to prepare a seafood for consumption is unusual. One method of Tiroi production is a lactic acid fermentation. SIGNIFICANCE AND IMPACT OF THE STUDY: If these foods are produced as described and are not either eaten immediately or cooked before consumption, then growth, and intoxication by, Clostridium botulinum might occur. 相似文献
14.
Alcoholic fermentation under Saccharomyces cerevisiae yeasts is governed largely by glucose uptake, biomass formation, ethanol and glycerin production, and acidification. In this work, PLS calibration models were developed with a view to determining these analytical parameters from near infrared spectra and analytical data provided by the corresponding reference methods. The models were applied to a set of samples obtained from various fermentation processes. The glucose, ethanol, and biomass values predicted by the models exhibited a high correlation with those provided by the reference method. 相似文献
15.
Hydrogen is a promising energy source that is believed to replace the conventional energy sources e.g. fossil fuels over years. Hydrogen production methods can be divided into conventional production methods which depend mainly on fossil fuels and alternative production methods including electrolysis of water, biophotolysis and fermentation hydrogen production from organic waste materials. Compared to the conventional methods, the alternative hydrogen production methods are less energy intensive and negative-value substrates i.e. waste materials can be used to produce hydrogen. Among the alternative methods, fermentation process including dark and photo-fermentation has gained more attention because these processes are simple, waste materials can be utilized, and high hydrogen yields can be achieved. The fermentation process is affected by several parameters such as type of inoculum, pH, temperature, substrate type and concentration, hydraulic retention time, etc. In order to achieve optimum hydrogen yields and maximum substrate degradation, the operating conditions of the fermentation process must be optimized. In this review, two routes for biohydrogen production as dark and photo-fermentation are discussed. Dark/photo-fermentation technology is a new approach that can be used to increase the hydrogen yield and improve the energy recovery from organic wastes. 相似文献
16.
Improved bioseparation techniques are increasingly important for biotechnology because separation is often the limiting factor for the success of biological processes. Manufacturers of new enzymes and pharmaceutical products require improved methods for recovering intact cells and intracellular products. Similarly the isolation, purification and concentration of many biomolecules produced in fermentation processes is extremely important. Often such downstream processing contributes a large portion of the product cost and thus efficient and economical alternative approaches to bioseparation processes are needed to eliminate, reduce or facilitate the handling of solids. Field-assisted separations, which hold immense potential for providing a major improvement in bioseparation in the near future, are considered in this review. Special emphasis is given to multistage methods, which are cost-effective compared with competing technologies. Commercial applications of these methods are detailed, we present suggestions for future work and we analyse the scale-up and economic aspects of these processes. 相似文献
17.
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. 相似文献
18.
Microbial synthesis of SCP on hydrocarbons is regaining importance. Improved methods of energetic balancing allow its economic assessment also under conditions denying direct proportionality between costs and social expenditures. Main methods for augmenting economy of SCP synthesis are recovery of further products beyond SCP, simplification of downstream processes, and rise in yield and productivity of fermentation. 相似文献
19.
Fermentation processes have been developed for producing most of the essential amino acids. Methionine is one exception. Although microbial production of methionine has been attempted, no commercial bioproduction exists. Here, we discuss the prospects of producing methionine by fermentation. A detailed account is given of methionine biosynthesis and its regulation in some potential producer microorganisms. Problems associated with isolation of methionine overproducing strains are discussed. Approaches to selecting microorganism having relaxed and complex regulatory control mechanisms for methionine biosynthesis are examined. The importance of fermentation media composition and culture conditions for methionine production is assessed and methods for recovering methionine from fermentation broth are considered. 相似文献
20.
Industrial production of citric acid through the fermentation processes of fungi is being carried on by three companies in the United States. Application of recently developed submerged culture methods have produced yields as great as those obtained by the longer established surface culture technique. 相似文献
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