Enhanced 2,3-butanediol production by Klebsiella pneumoniae SDM

State Key Laboratory of Microbial Technology, Shandong University, Jinan, 250100, People's Republic of China.
Applied Microbiology and Biotechnology (Impact Factor: 3.34). 11/2008; 82(1):49-57. DOI: 10.1007/s00253-008-1732-7
Source: PubMed


Enhanced 2,3-butanediol (BD) production was carried out by Klebsiella pneumoniae SDM. The nutritional requirements for BD production by K. pneumoniae SDM were optimized statistically in shake flask fermentations. Corn steep liquor powder and (NH(4))(2)HPO(4) were identified as the most significant factors by the two-level Plackett-Burman design. Steepest ascent experiments were applied to approach the optimal region of the two factors and a central composite design was employed to determine their optimal levels. The optimal medium was used to perform fed-batch fermentations with K. pneumoniae SDM. BD production was then studied in a 5-l bioreactor applying different fed-batch strategies, including pulse fed batch, constant feed rate fed batch, constant residual glucose concentration fed batch, and exponential fed batch. The maximum BD concentration of 150 g/l at 38 h with a diol productivity of 4.21 g/l h was obtained by the constant residual glucose concentration feeding strategy. To the best of our knowledge, these results were new records on BD fermentation.

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Available from: Lixiang Li, May 15, 2014
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    • "carbohydrates, the greatest conversion rates were achieved by glucose fermentation (Ma et al. 2009; Sun et al. 2009), but the high cost of the sugar substrates has been identified as a major factor affecting the economic viability of this biotechnology. The advanced microbial technologies for 2,3-BD synthesis are devoted to the reduction of expenses by the use of cheaper and renewable substrates of cellulosic and non-cellulosic origin. "
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    ABSTRACT: 2,3-Butanediol (2,3-BD) is an organic compound, which is widely used as a fuel and fuel additive and applied in chemical, food, and pharmaceutical industries. Contemporary strategies for its economic synthesis include the development of microbial technologies that use starch as cheap and renewable feedstock. The present work encompasses the metabolic engineering of the excellent 2,3-BD producer Klebsiella pneumoniae G31. In order to perform direct starch conversion into 2,3-BD, the amyL gene encoding quite active, liquefying α-amylase in Bacillus licheniformis was cloned under lac promoter control in the recombinant K. pneumoniae G31-A. The enhanced extracellular over-expression of amyL led to the highest extracellular amylase activity (68 U/ml) ever detected in Klebsiella. The recombinant strain was capable of simultaneous saccharification and fermentation (SSF) of potato starch to 2,3-BD. In SSF batch process by the use of 200 g/l starch, the amount of total diols produced was 60.9 g/l (53.8 g/l 2,3-BD and 7.1 g/l acetoin), corresponding to 0.31 g/g conversion rate. The presented results are the first to show successful starch conversion to 2,3-BD by K. pneumoniae in a one-step process.
    Applied Microbiology and Biotechnology 12/2013; 98(6). DOI:10.1007/s00253-013-5418-4 · 3.34 Impact Factor
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    • "Serratia marcescens produces meso-2,3-butanediol as the major product [11]. Other strains including Klebsiella pneumoniae, Klebsiella oxytoca, and Enterobacter cloacae produce meso-2,3-butanediol and (2S,3S)-2,3-butanediol as the major products [4,5,9]. In this study, a commercial 2,3-butanediol, which contained 15.9% (2R,3R)-2,3-butanediol, 76.1% meso-2,3-butanediol, and 8.0% (2S,3S)-2,3-butanediol, was used as the carbon source for G. oxydans DSM 2003. "
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    ABSTRACT: 2,3-Butanediol is a platform and fuel biochemical that can be efficiently produced from biomass. However, a value-added process for this chemical has not yet been developed. To expand the utilization of 2,3-butanediol produced from biomass, an improved derivative process of 2,3-butanediol is desirable. In this study, a Gluconobacter oxydans strain DSM 2003 was found to have the ability to transform 2,3-butanediol into acetoin, a high value feedstock that can be widely used in dairy and cosmetic products, and chemical synthesis. All three stereoisomers, meso-2,3-butanediol, (2R,3R)-2,3-butanediol, and (2S,3S)-2,3-butanediol, could be transformed into acetoin by the strain. After optimization of the bioconversion conditions, the optimum growth temperature for acetoin production by strain DSM 2003 was found to be 30[degree sign]C and the medium pH was 6.0. With an initial 2,3-butanediol concentration of 40 g/L, acetoin at a high concentration of 89.2 g/L was obtained from 2,3-butanediol by fed-batch bioconversion with a high productivity (1.24 g/L . h) and high yield (0.912 mol/mol). G. oxydans DSM 2003 is the first strain that can be used in the direct production of acetoin from 2,3-butanediol. The product concentration and yield of the novel process are both new records for acetoin production. The results demonstrate that the method developed in this study could provide a promising process for efficient acetoin production and industrially produced 2,3-butanediol utilization.
    Biotechnology for Biofuels 10/2013; 6(1):155. DOI:10.1186/1754-6834-6-155 · 6.04 Impact Factor
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    • "Various strains such as Bacillus polymyxa [6], Serratia marcescens [7], Klebsiella oxytoca [8] and K. pneumoniae [9] produce high 2,3-BD titers from a broad spectrum of substrates. However, the pathogenic nature of these organisms precludes their use in industrial-scale 2,3-BD fermentation [5,10]. "
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    ABSTRACT: Previously, a safe strain, Bacillus amyloliquefaciens B10-127 was identified as an excellent candidate for industrial-scale microbial fermentation of 2,3-butanediol (2,3-BD). However, B. amyloliquefaciens fermentation yields large quantities of acetoin, lactate and succinate as by-products, and the 2,3-BD yield remains prohibitively low for commercial production. In the 2,3-butanediol metabolic pathway, glyceraldehyde-3-phosphate dehydrogenase (GAPDH) catalyzes the conversion of 3-phosphate glyceraldehyde to 1,3-bisphosphoglycerate, with concomitant reduction of NAD(+) to NADH. In the same pathway, 2,3-BD dehydrogenase (BDH) catalyzes the conversion of acetoin to 2,3-BD with concomitant oxidation of NADH to NAD(+). In this study, to improve 2,3-BD production, we first over-produced NAD(+)-dependent GAPDH and NADH-dependent BDH in B. amyloliquefaciens. Excess GAPDH reduced the fermentation time, increased the 2,3-BD yield by 12.7%, and decreased the acetoin titer by 44.3%. However, the process also enhanced lactate and succinate production. Excess BDH increased the 2,3-BD yield by 16.6% while decreasing acetoin, lactate and succinate production, but prolonged the fermentation time. When BDH and GAPDH were co-overproduced in B. amyloliquefaciens, the fermentation time was reduced. Furthermore, in the NADH-dependent pathways, the molar yield of 2,3-BD was increased by 22.7%, while those of acetoin, lactate and succinate were reduced by 80.8%, 33.3% and 39.5%, relative to the parent strain. In fed-batch fermentations, the 2,3-BD concentration was maximized at 132.9 g/l after 45 h, with a productivity of 2.95 g/l·h. Co-overexpression of bdh and gapA genes proved an effective method for enhancing 2,3-BD production and inhibiting the accumulation of unwanted by-products (acetoin, lactate and succinate). To our knowledge, we have attained the highest 2,3-BD fermentation yield thus far reported for safe microorganisms.
    PLoS ONE 10/2013; 8(10):e76149. DOI:10.1371/journal.pone.0076149 · 3.23 Impact Factor
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