9-15: Screening of microorganisms able to produce 1,3-propanediol and optimization of medium constituents using response surface methodology

Glycerol is utilized as a substrate in biotechnological route, which is renewable and can be easily obtained from byproduct of bio-diesel and soap manufacturing process. 1,3-Propanediol is an important chemical mainly used for the synthesis of polytrimethylene terephthalate(PTT) and other polyester fibers.

To find a microorganism with a high potential for producing 1,3-propanediol, we screened hundreds of microorganism using the colormetric assay. Finally five microorganisms were isolated from soil samples of garden and industrial area, which have higher yield more than control. The positive colonies that exhibited deep red color were picked up with sterile toothpick and transferred onto the new LB plates and grew overnight. The detection of 1,3-propanediol producer in aerobic condition, reduced the product cost and made the biological method of 1,3-propanediol production more attractive

Medium composition were optimized for 1,3-propanediol concentration from Klebsiella pneumoniae AJ4. Response surface methodology was applied for the significant fermentation factors identified by one-factor-at-a-time approach. The optimal media constituents were consisted of 108 g/L glycerol, 2.74 g/L peptone and 4.35 g/L ammonium sulfate. In this optimized medium, the maximum 1,3-propanediol concentration of 52.34 g/L.

References

1. B. R. Oh et al, Optimization of culture conditions for 1,3-propanediol production from crude glycerol by Klebsiella pneumoniae using response surface methodology, Biotechnology and Bioprocess Engineering. 13: 666-670

2. Xianghui Q et al. Saturation-mutagenesis in two positions distant from active site of a Klebsiella pneumoniae glycerol dehydratase identifies some highly active mutants, Journal of Biotechnology. 144 : 43–.50