Production of yeast chitin-glucan complex from biodiesel industry byproduct

Crude glycerol from the biodiesel industry was used as carbon source for high cell density fed-batch cultivation of Pichia pastoris aiming at producing a chitin-glucan complex (CGC). More than 100 g L-1 biomass was obtained in less than 48 h. The yield of biomass on a glycerol basis was 0.55 g g(-1) during the batch phase and 0.63 g g(-1) during the fed-batch phase.The chitin-glucan complex was recovered from the yeast cell wall by hot alkaline extraction. CGC content in the cell wall was found to be relatively constant throughout the cultivation (18-26%) with a volumetric productivity of 1.28 g L-1 h(-1) at the end of the fed-batch phase. The molar ratio of chitin:beta-glucan in the extracted biopolymer was 16:84, close to other CGC extracted from Aspergillus biomass. The extracted polymer was characterized by Differential Scanning Calorimetry (DCS) and solid-state Nuclear Magnetic Resonance (NMR) spectroscopy and compared with commercial biopolymers, namely, crab shell chitin and/or chitosan, algal beta-glucan (laminarin) and fungal chitin-glucan complex (kiOsmetine). (C) 2012 Elsevier Ltd. All rights reserved.