Microbial 2,3-butanediol production: A state-of-the-art review

Biotechnological production of 2,3-butanediol—Current state and prospects

Production of 1,3-propanediol, 2,3-butanediol and ethanol by a newly isolated Klebsiella oxytoca strain growing on biodiesel-derived glycerol based media

Background
Acetoin and 2,3-butanediol are two important biorefinery platform chemicals. They are currently fermented below 40°C using mesophilic strains, but the processes often suffer from bacterial contamination.

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Thermophilic fermentation of acetoin and 2,3-butanediol by a novel Geobacillus strain

In the current study, a GRAS (Generally Recognized As Safe) strain of Bacillus amyloliquefaciens producing 2,3-butanediol (2,3-BD) designated as B10-127 was isolated in our lab. The strain B10-127 produced 2,3-BD effectively under the condition of 20% glucose (quality concentration), showed a high-glucose tolerance. The effects of initial glucose concentration, temperature, pH and agitation on 2,3-BD production were investigated in this work and the proper parameters were identified. Accordingly, the fed-batch culture of B10-127 in larger scales (5 l) showed a remarkable 2,3-BD producing potency. The maximum 2,3-BD concentration reached 92.3 g/l at 96 h with a 2,3-BD productivity of 0.96 g/l h. To our knowledge, the results were new records on 2,3-BD fermentation by Bacillus, which shown an excellent candidate for the microbial fermentation of 2,3-BD on an industrial scale.

Production of 2,3‐butanediol from glucose by GRAS microorganism Bacillus amyloliquefaciens

Most studies on 2,3-butanediol production by microbial fermentation have been carried out using Klebsiella oxytoca and Bacillus polymyxa. In these fermentations there is a significant conversion of carbon source into ethanol, glycerol and various organic acids as by-products. On the other hand, this investigation has shown that the major products of fermentation by Bacillus amyloliquefaciens are 2,3-butanediol and some minor acids. In a typical fermentation about 33 g of butanediol was produced from 100 g of glucose.



The effect of pH, various carbohydrate source, initial glucose concentration and aeration on the 2,3-butanediol fermentation by B. amyloliquefaciens were investigated. The butanediol productivity and yield was found to be highest with glucose as the carbohydrate source. The glucose concentration was varied between 30 and 100 g dm−3 with oxygen transfer rate controlled between 47.5 and 78.0 h−1. Oxygen and the initial substrate concentrations significantly influence the yield, productivity and by-product formation.

S. Alam

Papers

Kinetics of 2,3‐butanediol fermentation by Bacillus amyloliquefaciens: Effect of initial substrate concentration and aeration