Lipid production by Cryptococcus curvatus growing on commercial xylose and subsequent valorization of fermentation waste-waters for the production of edible and medicinal mushrooms

摘要

A rarely studied Cryptoccus curvatus strain (viz. NRRL Y-1511) was cultivated in shake-flask submerged nitrogen-limited experiments, with commercial xylose being employed as substrate and has been proved as quite appropriate for total biomass, lipid and endopolysaccharide production. A batch bioreactor trial compared to the equivalent shake-flask experiment showed larger amounts of total lipid and biomass produced. Total dry biomass of 26.1 g/L containing c. 30 % of lipids was synthesized. Endopolysaccharides in relatively high concentrations were synthesized in the early growth stages decreasing afterwards in favor of storage lipid synthesis. Lipid production bioprocess was successfully simulated by a modified Velruyten-Aggelis model and the optimized parameter values were found to be similar to those experimentally measured. Lipids contained mostly neutral fractions (triacylglycerols) and were rich in the fatty acid Delta 9C18:1, constituting a suitable starting material for the synthesis of high-quality biodiesel. Within the frame of bio-refinery, lipid fermentation waste-waters were used as maceration waters for a novel mushroom cultivation process of Pleurotus ostreatus, Lentinula edodes and Ganoderma adspersum edible and medicinal mushrooms. These waste-waters were used for first time in mushroom cultivation process demonstrating positive effect on laccase and sporophore production by these mushroom species.