Title
Corn cob hydrolyzates used for microbial biosynthesis of polyhydroxybutyrate
Authors
IRINA STOICA ANCA ROXANA PETROVICI MIHAELA SILION CRISTIANDRAGOS VARGANICI RODICA DINICA and GABRIELA BAHRIM

Received April 06, 2017
Published Volume 52 Issue 1-2 January-February
Keywords corn cobs, dilute-acid hydrolysis, Bacillus spp., polyhydroxybutyrate (PHB)

Abstract
A new fermentation strategy to obtain polyhydroxybutyrate (PHB) with selected bacteria, using a sustainable raw material as the single carbon source, was analyzed. Corn cob dilute-acid hydrolyzates were obtained and used as a carbon source for a fermentative medium formulation to cultivate spore-forming bacteria in order to achieve biopolymer biosynthesis. Different methods for the hydrolysis of the raw material and for assessing the content of fermentescible sugars of the hydrolyzates were tested. The dilute-acid hydrolyzate with 35.84 g/L total sugars content assured the optimum fermentative conditions for microbial growth and PHB bioproduction by the selected strain Bacillus spp. BM 37. The intracellular polymer production and its structure were analyzed by HPLC-MS and NMR analyses. The yield of PHB produced after the cultivation of the selected bacteria, under submerged aerobic conditions, in liquid medium based on corn cob hydrolyzate, was 36.16% w/w dry biomass, which is comparable to the results reported in the literature. Our findings offer valuable perspectives regarding the use of corn cob agro-waste resources for the formulation of a fermentation medium by an economical biotechnological approach.