On-line identification of fermentation processes for ethanol production

Bioprocess and Biosystems Engineering - A strategy for monitoring fermentation processes, specifically, simultaneous saccharification and fermentation (SSF) of corn mash, was developed. The...     

Use of an Extended Kalman Filter and development of an automated system for xylose fermentation by a recombinantEscherichia coli

Summary An automated system was developed for on-line monitoring and control of xylose fermentation by a recombinantEscherichia coli. A 7-L fermenter was interfaced with a personal computer. Control circuits were constructed and a software was developed to estimate the states of the fermentation using an Extended Kalman Filter. The automated system combined with the Extended Kalman Filter provided a satisfactory way to obtain on-line information regarding estimation of fermentation parameters.     

Factors mediating the ethanol fermentation of glucose in high corn media

Biotechnology Letters - A non-saccharified corn substrate system was developed to study the Saccharomyces cerevisiae alcohol fermentation. It appeared that the factors mediating the fermentation of...     

A novel solid-state fermentation system using polyurethane foam as inert carrier

Summary A novel solid-state fermentation method using polyurethane foam as inert carrier impregnated with a synthetic liquid medium was developed simulating the nutritional composition and culture conditions of solid-state fermentation on wheat bran. With this system, biomass, the important parameter involved in solid-state fermentation processes, can be measured directly. Some other superiorities of this system over conventional solid-state fermentation systems are discussed.     

Modelling of the glucosinolate content in solid-state fermentation of rapeseed meal with fuzzy logic

A fuzzy model was developed to predict the glucosinolate content of rapeseed meal during solid-state fermentation. Process variables such as temperature, relative humidity, fermentation time and the resulting glucosinolate content of the meal were considered. The glucosinolate content calculated by the fuzzy model corresponded with the experimental results obtained by solid-state fermentation.     

Production and isolation of chitosan by submerged and solid-state fermentation from Lentinus edodes

A method for the laboratory-scale production and isolation of chitosan (polyglucosamine) by liquid and solidstate fermentation from Lentinus edodes was developed. The yields of isolated chitosan were 120 mg/L of fermentation medium under liquid fermentation conditions and 6.18 g/kg of fermentation medium under solid-state fermentation conditions. The latter method, which gives up to 50 times yields than other chitosan production methods from fungi, provides a new flexible and easily scaledup procedure for the production of low acetylation degree chitosan. (c) 1996 John Wiley & Sons, Inc.     

Carbohydrate Fermentation Patterns of Neisseria meningitidis Determined by a Microtiter Method

A carbohydrate fermentation technique has been developed and compared to the standard fermentation test with cystine-Trypticase-semisolid agar for the identification of Neisseria meningitidis. This new method utilizes Mueller-Hinton broth as a basal substrate and is performed with microtiter methods. By using Mueller-Hinton broth with and without the addition of antibiotics, the method can be adjusted to test the fermentation patterns of all of the Neisseria including N. gonorrhoeae.     

Computer controlled fed-batch fermentation of the methylotroph Pseudomonas AM1

Summary A simple on-line computer control strategy based on dissolved oxygen level readings has been developed to control methanol addition during a fermentation of the methylotroph Pseudomonas AM1. This strategy has led to significant and reproducible improvements in the performance of the fermentation.     

Image analysis for monitoring the barley tempeh fermentation process

AIMS: To develop a fast, accurate, objective and nondestructive method for monitoring barley tempeh fermentation. METHODS AND RESULTS: Barley tempeh is a food made from pearled barley grains fermented with Rhizopus oligosporus. Rhizopus oligosporus growth is important for tempeh quality, but quantifying its growth is difficult and laborious. A system was developed for analysing digital images of fermentation stages using two image processing methods. The first employed statistical measures sensitive to image colour and surface structure, and these statistical measures were highly correlated (r=0.92, n=75, P<0.001) with ergosterol content of tempeh fermented with R. oligosporus and lactic acid bacteria (LAB). In the second method, an image-processing algorithm optimized to changes in images of final tempeh products was developed to measure number of visible barley grains. A threshold of 5 visible grains per Petri dish indicated complete tempeh fermentation. When images of tempeh cakes fermented with different inoculation levels of R. oligosporus were analysed the results from the two image processing methods were in good agreement. CONCLUSION: Image processing proved suitable for monitoring barley tempeh fermentation. The method avoids sampling, is nonintrusive, and only requires a digital camera with good resolution and image analysis software. SIGNIFICANCE AND IMPACT OF THE STUDY: The system provides a rapid visualization of tempeh product maturation and qualities during fermentation. Automated online monitoring of tempeh fermentation by coupling automated image acquisition with image processing software could be further developed for process control.     

溶氧对L-苏氨酸发酵的影响

探索溶氧对L-苏氨酸发酵过程的影响及其控制方法。通过摇瓶装液量试验、不同溶氧控制方式考察发酵过程中溶氧对L-苏氨酸合成的影响。采用补料分批发酵工艺发酵L-苏氨酸,利用氨基酸分析仪测定发酵液中L-苏氨酸的产量,通过10L罐补料分批发酵36h,产酸可达118.9g/L,糖酸转化率为47.6%。可以得出溶氧对L-苏氨酸生物合成有重要影响,并建立了最佳溶氧控制条件。     

Kinetic model for the bioconversion of glucose to 2,5-diketo-D-gluconic acid

Summary A simple unstructured mathematical model for the oxidation of glucose to 2,5-diketo-D-gluconic acid with Erwinia citreus was developed. The kinetic parameters of the model were estimated by the oxygen partial pressure method and directly from the temporal response obtained from the experimental data collected in the batch fermentation. The simple developed model based on the kinetic measurements was able to simulate quite well the dynamic behaviour of the batch fermentation.     

Rapid Fermentation Confirmation of Neisseria gonorrhoeae

A rapid sugar fermentation procedure has been developed for the confirmation of Neisseria gonorrhoeae from either primary isolation media or purification media. A lightly buffered salt solution with pH indicator and sugars was heavily inoculated with presumptively positive growth. Proper fermentation patterns are obtained in 1 to 4 h with no interference from inhibited contaminants or variation in results due to differing growth requirements of gonococcal strains.     

三相流化床L-乳酸发酵及与离子交换分离耦合

L—乳酸因其能被人体代谢而将在食品、医药工业中代替DL—乳酸。另外均聚和共聚L—乳酸在医学及生产可生物降解的包装材料、农膜等方面有巨大的潜在市场。L—乳酸一般采用米根霉     

A scaleable manufacturing process for pro-EP-B2, a cysteine protease from barley indicated for celiac sprue

Celiac Sprue is an inflammatory disease of the small intestine triggered by ingestion of dietary gluten, a family of glutamine and proline rich proteins found in common foodgrains such as wheat, rye, and barley. One potential therapy for this lifelong disease anticipates using an oral protease to detoxify gluten in vivo. Recent studies have shown that EP-B2 (endoprotease B, isoform 2) from barley is a promising example of such a glutenase, thus warranting its large-scale production for animal safety and human clinical studies. Here we describe a scaleable fermentation, refolding and purification process for the production of gram to kilogram quantities of pro-EP-B2 (zymogen form of EP-B2) in a lyophilized form. A fed-batch E. coli fermentation system was developed that yields 0.3-0.5 g purified recombinant protein per liter culture volume. Intracellular degradation of pro-EP-B2 during the fermentation was overcome by manipulating the fermentation temperature and duration of protein expression. A simple refolding protocol was developed using a fast dilution method to refold the enzyme at concentrations greater than 0.5 mg/mL. Kinetic analysis showed that pro-EP-B2 refolding is a first-order reaction with an estimated rate constant of 0.15 h(-1). A lyophilization procedure was developed that yielded protein with 85% recoverable activity after 7 weeks of storage at room temperature. The process was successfully scaled up to 100 L with comparable purity and recovery.     

Determination of 5alpha-androst-16-en-3alpha-ol in truffle fermentation broth by solid-phase extraction coupled with gas chromatography-flame ionization detector/electron impact mass spectrometry

A novel method using solid-phase extraction coupled with gas chromatography and flame ionization detector (FID)/electron impact mass spectrometry (EIMS) was developed for the determination of 5alpha-androst-16-en-3alpha-ol (androstenol), a steroidal compound belonging to the group of musk odorous 16-androstenes, in truffle fermentation broth. Comparison studies between FID and EIMS indicated two detectors gave similar quantitative results. The highest androstenol concentration of 123.5 ng/mL was detected in Tuber indicum fermentation broth, while no androstenol was found in Tuber aestivum fermentation broth. For the first time, this work confirmed the existence of androstenol in the truffle fermentation broth, which suggested truffle fermentation is a promising alternative for androstenol production on a large scale.     

Simultaneous measurements of oxygen diffusion coefficients and solubilities in fermentation media with polarographic oxygen electrodes

A membrane-covered oxygen electrode was used to measure oxygen diffusion coefficients and solubilities in aqueous glucose solutions and various fermentation media following a newly developed methodology. The fermentation media studied were tryptic soy broth and those for fermentations of Penicillium chrysogenum, Saccharomyces cerevisiae, and Micrococcus glutamicus. The experimental results of oxygen diffusion coefficients and solubilities in glucose solutions were in good accord with the literature data. As for the fermentation media, both oxygen diffusion coefficients and solubilities were found to decrease with an increased fractional composition of these media, and log-additive behaviors of the oxygen diffusion coefficients and solubilities in fermentation media were observed.     

柑橘果实加工废料资源化新技术研究

本文报道柑橘果实加工废料经直接压榨,并利用微生物发酵制取乙醇、橙皮甙及饲料等新技术。乙醇、橙皮甙产品经检验达A.R.级;饲料中脂肪、蛋白质含量分别比发酵前提高了175.7%和51.1%。制备全过程不产生污染,便于产业化。     

Batch kinetics of microbial polysaccharide biosynthesis

A modified form of logistic equation has been proposed to quantity the batch kinetics of microbial growth during the biosynthesis of extra- and intracellular polymers. Based on the experimental data developed in this study, the proposed model appeared to provide adequate growth and fermentation kinetics of Aureobasidium pullulans. The model was also applicable for representing the reported data on pullulan, xanthan, and poly-beta-hydroxybutyricacid. In comparison to the logistic and Monod kinetics, this model fitted the data better and more accurately described the overall fermentation, both concentrations and fermentation time.     

A bioenergetic model of a mixed production fermentation

A bioenergetic model has been developed for the fermentation of glucose by Bacillus polymyxa. This model uses energy balances to determine which pathways are utilized by the substrate. The model can predict substrate consumption, biomass formation, and the product distribution for this fermentation. The products are carbon dioxide, water, 2,3-butanediol, and ethanol, where ethanol represents lumped anaerobic products.     

Use of fluorometry for monitoring and control of a bioreactor

A new fluorescent bioreactor monitoring probe-multiple excitation fluorometric system (MEFS)-has been developed. This probe was compared to the commercially available BioChem Technology FluroMeasure system (NADH probe). In this task the fluorescence behavior of three model fermentation systems, ethanol fermentation by Candida utilis, phenol fermentation by Pseudomonas putida, and glucose fermentation by Saccharomyces cerevisiae, were examined. The results indicated that the fluorescence intensity and behavior of various cellular fluorophors vary significantly between the different fermentation systems. Monitoring a fermentation process using only NAD(P)H fluorescence provided limited information. The NAD(P)H fluorescence was found not to be the best fluorescence signal for monitoring cell concentrations. The best way of monitoring a bioreactor by fluorometry may be to monitor several fluorophors in the whole culture broth simultaneously and to relate these fluorescence signals to various biological parameters.