PROCESS OPTIMISATION OF 1,3-PROPANEDIOL PRODUCTION BY Klebsiella pneumoniae STRAIN

Abstract

The 1,3-propanediol (1,3-PD) is a versatile chemical feedstock with a wide range of applications: cosmetic, food and polymers synthesis. Although 1,3-PD is conventionally chemically synthesised, it has drawbacks such as requiring high pressure and temperature. Therefore, a more economical biological approach to produce 1,3-PD is crucial. This study attempted to investigate the effects of common fermentation parameterstemperature, pH, glycerol concentration and inoculum size on the production of 1,3-PD by Klebsiella pneumoniae via one-factor-at-a-time (OFAT) method. The optimised conditions: temperature, 34°C; pH, 7.5; glycerol concentration, 30 g litre-1 and inoculum size, 20% (v/v) showed 1.78-fold increase in 1,3-PD production, i.e. from the initial 4.89 g litre-1 to 8.70 g litre-1 in shake flask experiment after 48 hr. The 1,3-PD productivity by K. pneumoniae was higher (0.18 g litre-1 hr-1) from the unoptimised conditions (0.07 g litre-1 hr-1). The other parameter studied-varying nitrogen sources in the fermentation medium-revealed that their addition unexpectedly did not show any improvement in 1,3-PD production unlike those reported in the literature. It can be concluded that both glycerol concentration and incubation temperature were the most significant factors in producing higher 1,3-PD yield.