Microbial production alcohols

Although 2-phenylethanol can be synthesised by normal microbial metabolism, the final concentrations in the culture broth of selected microorganisms generally remain very low [110, 111] therefore, de novo synthesis cannot be a strategy for an economically viable bioprocesses. Nevertheless, the microbial production of 2-phenylethanol can be greatly increased by adding the amino acid L-phenylalanine to the medium. The commonly accepted route from l-phenylalanine to 2-phenylethanol in yeasts is by transamination of the amino acid to phenylpyruvate, decarboxylation to phenylacetaldehyde and reduction to the alcohol, first described by Ehrlich [112] and named after him (Scheme 23.8). 

V. L. Yarovenko Theory and Practice of Continuous Cultivation of Microorganisms in Industrial Alcoholic Processes. - Y. Miura Mechanism of Liquid Hydrocarbon Uptake by Microorganisms and Growth Kinetics. -J. E. Zajic, N. Kosaric, J. D. Brosseau Microbial Production of Hydrogen. - T.Enatsu, AShin-myo In vitro Synthesis of Enzymes. Physiological Aspects of Microbial Enzyme Production. 

RN Patel, CT Hou, AI Laskin, P Derelanko. Microbial production of methyl-ketones properties of purified yeast secondary alcohol dehydrogenase. J Appl Bio-chem 3 218-232, 1981. 

Some yeasts and bacteria are able to produce different alcohols like ethanol and butanol as well as polyols like glycerin and 2,3-butandiol. These compounds- are used in drinks such as beer and wines, and also may be used in or as solvents, drugs, chemicals, oils, waxes, lacquers, antifreezing and antifoaming agents, precipitants, dyestuff, pomades, raw materials for chemical syntheses, motor fuels, and carbon sources for SCP production. These products are mainly synthesized from petroleum — derived materials like ethylene and acetaldehyde. However, because of the insufficient availability and high prices of the raw materials, the microbial production of alcohols has become an interesting area for many researchers. 

Many important fine chemicals, including catechols, phenols, aldehydes and ketones, low molecular epoxides and diepoxides, medixun-chain alcohols, and terpenoids fall within the range of 1 < log Pq/w < 4. The discovery of solvent-tolerant bacteria leads to the new possibility of biocatalytic reaction systems containing organic solvents. By using solvent-tolerant bacteria, a variety of fine chemicals can be formed in microbial production processes. 

The Access Code for the Microbial Production of Branched-Chain Alcohols 2-Ketoacid Decarboxylase and an Alcohol Dehydrogenase... 

THE ACCESS CODE FOR THE MICROBIAL PRODUCTION OF BRANCHED-CHAIN ALCOHOLS... 

In 2011, San Diego-based Genomatica demonstrated industrial-scale microbial production from glucose of 1,4-butanediol, an organic alcohol used around the world in quantities of about 1 million metric tons per year as a solvent and in the manufacture of plastics, polyurethane, polyesters, tetrahydrofuran, and other materials. The conventional chemical synthesis of... 

Zhang CM, Adesina AA, Wainwright MS (2002b) Solubility studies of isobutene in tertiary butyl alcohol + water mixtures. J Chem Eng Data 47(6) 1476-1480 Zheng YN et al (2009) Problems with the microbial production of butanol. J Ind Microbiol... 

Prior to the widespread awdlabdity of recombiant carbonyl reductases enzymes, the use of microbial reductions using either actively growing or dormant cells was commonplace Bakers yeast in particular, was a readily available source of stereoselective carbonyl reductases enzymes. Even with the widespread knowledge of the power of recombinant CRED biocatalysts, the literature is still rife with wild-type whole-cell microbial reductions. The reductions presented have advanced well beyond the early Bakers yeast reduction and have an apphcation even today. When the whole-cell fermentation is developed and finely tuned, high titers of product alcohol are possible and Scheme 6.4 shows m example of a keto-amide 12 bioreduction performing at 100 g/L with more than 98% ee with multi-kg isolation [12]. The bioprocess was performed over 8 days at pH 7 using the yeast Candida sorbophila. 

Because enzymes can be intraceUularly associated with cell membranes, whole microbial cells, viable or nonviable, can be used to exploit the activity of one or more types of enzyme and cofactor regeneration, eg, alcohol production from sugar with yeast cells. Viable cells may be further stabilized by entrapment in aqueous gel beads or attached to the surface of spherical particles. Otherwise cells are usually homogenized and cross-linked with glutaraldehyde [111-30-8] to form an insoluble yet penetrable matrix. This is the method upon which the principal industrial appHcations of immobilized enzymes is based. 

Ethanol fermentation is a particularly good example of product accumulation inhibiting the microbial culture. Most strains of yeast have a much slower alcohol production rate when ethanol reaches about ten percent, and the wine or said strains that achieve over 20 percent by volume of ethanol are very, very slow. A system known as the Vacuferm for removal of alcohol by distillation as it is formed is... 

Microorganisms have been identified and exploited for more than a century. The Babylonians and Sumerians used yeast to prepare alcohol. There is a great history beyond fermentation processes, which explains the applications of microbial processes that resulted in the production of food and beverages. In the mid-nineteenth century, Louis Pasteur understood the role of microorganisms in fermented food, wine, alcohols, beverages, cheese, milk, yoghurt and other dairy products, fuels, and fine chemical industries. He identified many microbial processes and discovered the first principal role of fermentation, which was that microbes required substrate to produce primary and secondary metabolites, and end products. 

Utilising the usual levels of anti-microbials for cleansing products with normal user instructions of three minutes or longer contact time can achieve positive claims of anti-bacterial for Myavert C based enzyme preservation system without the stinging associated with alcohol. Table 1 gives the plate kill speed data for a face masque where the preservative also becomes a positive attribute. 

Kataoka, M., Hoshino-Hasegawa, A., Thiwthong, R. et al. (2006) Gene cloning of an NADPH-dependent menadione reductase from Candidamacedoniensis, and its application to chiral alcohol production. Enzyme and Microbial Technology, 38 (7), 944—951. 

This gum was the first microbial gum to be used in the food industry. It is produced by the aerobic fermentation of Xanthomonas campestris. A specially selected culture is grown on a carbohydrate-containing nutrient medium with a nitrogen source and other essential elements. The pH, temperature and aeration are controlled carefully. The product is then sterilised and the gum is precipitated with propan-2-ol. Next, the precipitate is washed, then pressed to remove residual alcohol, followed by drying and grinding to the required size. 

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