Showing papers on "2,3-Butanediol published in 2005"

Development of industrial-medium-required elimination of the 2,3-butanediol fermentation pathway to maintain ethanol yield in an ethanologenic strain of Klebsiella oxytoca.

Abstract: Fermentation efficiency and nutrient costs are both significant factors in process economics for the microbial conversion of cellulosic biomass to commodity chemicals such as ethanol. In this study, we have developed a more industrial medium (OUM1) composed of 0.5% corn steep liquor (dry weight basis) supplemented with mineral salts (0.2%), urea (0.06%), and glucose (9%). Although the growth of strain P2 was vigorous in this medium, approximately 14% of substrate carbon was diverted into 2,3-butanediol and acetoin under the low pH conditions needed for optimal cellulase activity during simultaneous saccharification. Deleting the central region of the budAB genes encoding α-acetolactate synthase and α-acetolactate decarboxylase eliminated the butanediol and acetoin coproducts and increased ethanol yields by 12%. In OUM1 medium at pH 5.2, strain BW21 produced over 4% ethanol in 48 h (0.47 g ethanol per g glucose). Average productivity (48 h), ethanol titer, and ethanol yield for BW21 in OUM1 medium (pH 5.2) exceeded that of the parent (strain P2) in rich laboratory medium (Luria broth).

1, 3-propylene glycol and 2, 3-butanediol production method using glecerol by microorganism two-step fermentation method

Abstract: The invention discloses a method for simultaneously preparing 1,3-propylene glycol and 2,3-butylene glycol from glycerol by using microbe employing prior-stage anaerobic and later-stage aerobic two-stage fermentation process, which belongs to the field of the bio-chemical engineering technology. In the fermentation process, the seed liquid is added in the primary fermentation medium containing industrial glycerol or glycerol fermentation liquid, after 3i½5 hours, the mixed liquid of glycerol and glucose is added in the form of the flow. The product concentrations of 1,3-propylene glycol and 2,3-butylene glycol are controlled by adjusting the air flow in the two-stage fermentation process and controlling the fermentation temperature. When the fermentation process is over, 1,3-propylene glycol and 2,3-butylene glycol are separated and purified by desalting, distilling, and vacuum rectification. The preparing method can improve the fermentation concentration and the yield of 1,3-propylene glycol and the production intensity, at the same time, 2,3-butylene glycol with higher concentration can be obtained with high raw material availability and low cost.

Preparation of the four stereoisomers of 3-bromo-2-butanol or their acetates via lipase-catalysed resolutions of the racemates derived from dl- or meso-2,3-butanediol

Abstract: The four stereoisomeric 3-bromo-2-butanols and/or their acetates were prepared via lipase-catalysed kinetic resolution by hydrolyses of the acetates of the (+/-)-syn- and (+/-)-anti-3-bromo-2-but ...