Fermentative Production of 1 3 PDO and 2 3 BDO using poly-vinyl-alcohol immobilized cells of Klebsiella sp ZMD30

Abstract

1 3-Propanediol (1 3-PDO) an important platform chemical is widely used in cosmetic food lubricant and pharmaceutical industries 2 3-BDO (2 3-butanediol) is a key ingredient used in a variety of industries such as food cosmetics pharmaceuticals plastics health care and energy 1 3-PDO and 2 3 BDO can be produced by microbial fermentation or chemical synthesis processes Fermentative production is more favorable since they can be produced under moderate reaction conditions via fermentation while chemical synthesis requires higher temperature (90°C) pressure (1500 psi) and expensive catalysts (such as cobalt) In this study Klebsiella sp Zmd30 is employed for the fermentative production of 1 3-PDO and 2 3-BDO since it has an outstanding tolerance for high concentrations of glycerol The fermentation was carried out using poly-vinyl-alcohol (PVA) immobilized Klebsiella sp Zmd30 and renewable feedstock High productivity was obtained under optimum condition (pH 6; agitation 200 rpm; 30oC; and aeration with fresh air 1 vvm) In this study we focused on the production of the 1 3-PDO using PVA immobilized cells of Klebsiella sp Zmd30 with different cell loading particle loading and aeration rate The optimum cell loading for 1 3-PDO was 0 28 g cells/g PVA leading to a maximum productivity of 0 788 g/l/h In terms of particle loading 20% (w/v) was the optimum particle loading with yield productivity and maximum concentration 0 6 mol/mol glycerol 1 5 g/l/h and 20 g/l Aeration at 1 vvm showed better performance than that of fermentation without aeration (0 vvm) Applying immobilized cells of Klebsiella sp ZMD30 and employing reactivation in between considerably enhanced the operational stability and reusability of the cells The immobilized cells could be used for four cycles and 70% of the initial productivity could be achieved compared to the first cycle The production of 2 3-BDO using PVA immobilized cells of Klebsiella sp Zmd30 from glucose was studied The variables employed are the same as used in 1 3-PDO production which are different cell loading particle loading and aeration rate The optimum cell loading for 2 3-BDO was 0 28 g cells/g PVA leading to a maximum VI productivity of 4 0 g/l/h In terms of particle loading 20% (w/v) was the optimum amount of particle loading which leads to 0 6 mol 2 3-BDO/mol glucose a maximum concentration of 10 2 g/l and a maximum productivity of 1 85 g/l/h Aeration at 1 vvm showed better performance than that of fermentation without aeration (0 vvm)

Date of Award	2018 Aug 28
Original language	English
Supervisor	Jo-Shu Chang (Supervisor)