(20b) Mixture-Process Variable Experimental Design to Optimize Sugar Mixture (glucose, xylose and arabinose) Conversion to Polyhydroxybutyrate By Burkholderia Saccharia

Authors: 
Li, M., University of Nebraska-Lincoln
Wilkins, M. R., University of Nebraska-Lincoln
Eskridge, K., University of Nebraska-Lincoln
Polyhydroxybutyrate (PHB) is a biodegradable plastic that is comparable with some petroleum based plastics in terms of mechanical properties. Conversion of corn stover or corn fiber to PHB makes corn processing more profitable and sustainable. Glucose, xylose and arabinose are the main monomer sugars derived from either corn stover or corn fiber. Burkholderia sacchari DSM 17165 is a bacteria strain that can convert all three sugars into PHB. However, the effects of sugar ratio in mixture, process variable (sugar concentration, carbon to nitrogen ratio) and their interactions on PHB concentration and productivity is seldom studied. In this study, mixture-process variable experimental design is employed. Single factor experimental results showed that the optimal initial sugar concentrations and carbon to nitrogen molar ratios ranged from 10 to 40 g/L and 40 to 80 for different sugar mixture ratios. A ten run design for sugar ratio combined with a full factorial design for optimizing process variables will be performed to optimize PHB production.