Alcoholic fermentations, immobilized

Alcoholic fermentations, immobilized systems and aqueous two-phase systems, 80... 

Much effort has gone, in recent years, in setting up alcoholic fermentations based on immobilized cell technology (J)). Some of the systems have proved to be highly productive, but are faced with drawbacks of leakage of cells, and sterical hindrances. Fermentation in two-phase system, on the other hand, has been successfully carried out with macromolecular substrates such as starch and cellulose (7 10 ). It is also easier to control a reaction system involving a number of enzymes, in a two-phase system as compared to the immobilized systems for example, there is a possibility to add more of the labile catalyst during the continuous operations. 

These examples indicate the in situ applicability of enzyme electrodes however, numerous problems have still to be solved. At present, coupling of enzyme sensors for fermentation control in a bypass arrangement appears to be more favorable [412]. Following this concept, an invertase thermistor incorporating a sterilizable filter unit has been developed [413] for the monitoring of alcoholic fermentation by immobilized yeast cells. Another thermistor has been successfully used for on-line glucose measurement under real cultivation conditions of Cephalosporium acremonium [414]. Similar calorimetric devices are suitable for other fermentation processes and in environmental analysis. 

Nano/microporous cellulose (NMC) prepared after removal of lignin from wood cellulose was found suitable for the development of cold pasteurization" processes acting as a biofilter for cell removal. It was also used successfully as biocatalyst in food fermentations acting as both cell immobilization carrier and as promoter of biochemical reactions, even at extremely low temperatures. The cumulative surface area of the NMC pores was found to be 0.8 to 0.89 m g" as indicated by porosimetry analysis. This surface is relatively small compared with other porous materials such as y-alumina however, using a natural organic material is attractive from the point of view that it is safer for bioprocess applications and is better accepted by consumers. The NMC/immobilized yeast biocatalyst increased the fermentation rate and was more effective at lower temperatures compared with free cells. Furthermore, the activation energy E, of fermentation was found to be 28% lower than that of free cells, indicating that it is an excellent material to promote the catalytic action of cells for alcoholic fermentation. 

Plessas S., Bekatorou A., Koutinas A.A., Soupioni M., Banatl.M. andMarchantR.UseofSaccharomyces cerevisiae cells immobilized on orange peel as biocatalyst for alcoholic fermentation. Bioresource... 

Because the presence of yeasts can represent a logistical bottleneck in postfermentation clarification, an alternative that has been studied is the use of immobilized microorganisms. Here, yeasts are trapped in calcium alginate beads or strands that are collectively packed into a synthetic mesh sleeve that is immersed into the juice/must. Relatively few yeasts (<10V mL) escape the encapsulation matrix (Yokotsuka et al., 1993) but yet conduct an active alcoholic fermentation. Yajima and Yokotsuka (2001) reported that concentrations of some undesirable volatile compounds (methanol, ethyl acetate, and acetaldehyde) were lower in wines made using Saccharomyces immobilized in double-layer beads. Immobilized yeasts... 

Yokotsuka, K., a. Otaki, A. Naitoh, and H. Tanaka. 1993. Controlled simultaneous deacidification and alcohol fermentation of a high-acid grape must using two immobilized yeasts, Schizosaccharomyces pombe and Saccharomyces cerevisiae. Am.]. Enol. Vitic. 44 371-377. 

P.J., Valenca, G.P. et al. (2013) Effect of immobilized cells in calcium alginate beads in alcoholic fermentation. AMB Express, 3, 31. 

In the early years of the chemical industry, use of biological agents centered on fermentation (qv) techniques for the production of food products, eg, vinegar (qv), cheeses (see Milk and milk products), beer (qv), and of simple organic compounds such as acetone (qv), ethanol (qv), and the butyl alcohols (qv). By the middle of the twentieth century, most simple organic chemicals were produced synthetically. Fermentation was used for food products and for more complex substances such as pharmaceuticals (qv) (see also Antibiotics). Moreover, supports were developed to immobilize enzymes for use in industrial processes such as the hydrolysis of starch (qv) (see Enzyme applications). 

Alcohol Sensor. On-line measurements of ethyl alcohol concentration in culture broth are required in fermentation industries. A microbial electrode consisting of immobilized yeasts or bacteria, a gas permeable Teflon membrane, and an oxygen electrode was prepared for the determination of methyl and ethyl alcohols(7). 

The use of immobilized cell systems is applicable to all fermentation schemes and is being researched extensively for the production of alcohols, chemicals, and biological products. 

Microbacteruim arborescens, Streptomyces rubiginosus var., or Streptomyces murinus) Produced as an off-white to tan, brown, or pink, amorphous powder, granules, or a liquid by controlled fermentation using any of the above-named organisms. The products may be soluble in water but practically insoluble in alcohol, in chloroform, and in ether, or if immobilized, may be insoluble in water and partially soluble in alcohol, in chloroform, and in ether. Major active principle glucose (or xylose) isomerase. Typical applications manufacture of high-fructose corn syrup and other fructose starch syrups. 

In an alternate process for the preparation of the C-13 paclitaxel side chain, the enantioselective enzymatic hydrolysis of racemic acetate ci5 -3-(acetyloxy)-4-phenyl-2-azetidinone 38 (Eignre 16.10B), to the corresponding (S)-alcohol 39 and the nnreacted desired (l )-acetate 38 was demonstrated [63] nsing lipase PS-30 from Pseudomonas cepacia (Amano International Enzyme Company) and BMS lipase (extracellnlar lipase derived from the fermentation of Pseudomonas sp. SC 13856). Reaction yields of more than 48% (theoretical maximnm yield 50%) with EEs greater than 99.5% were obtained for the (R)-38. BMS lipase and lipase PS-30 were immobilized on Accnrel polypropylene (PP), and the immobilized lipases were reused (10 cycles) without loss of enzyme activity, productivity, or the EE of the product (R)-38. The enzymatic process was scaled up to 250 L (2.5 kg substrate input) using immobilized BMS lipase and lipase PS-30. Prom each reaction batch, R-acetate 38 was isolated in 45 mol% yield (theoretical maximum yield 50%) and 99.5% EE. The (R)-acetate was chemically converted to (R)-alcohol 39. The C-13 paclitaxel side-chain synthon (2R,3S-37 or R-39) produced by either the reductive or resolution process could be coupled to bacattin III 34 after protection and deprotection to prepare paclitaxel by a semisynthetic process [64]. 

Urease is industrially used to remove urea from alcoholic beverages in Japan (Kodama 1996). Removal of urea precludes the formation of toxic ethylcarbamate during fermentation, which is particularly relevant in the production of sake. The continuous process with immobilized Lactobacillus fermentum urease has been developed and optimized (Matsumoto 1993). 

Cellulosic materials are very popular as immobilization carriers for alcoholic beverage production, due to their food-grade purity, low cost, and availability all year round. Delignified cellulosic materials (DCMs) have been successfully used as carriers for the development of immobilized cell biocatalysts for use in various bioprocesses related to food and fuel industries such as alcoholic and lactic acid fermentations for alcoholic beverages and dairy products production. "... 

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