Production of Endopolysaccharides from Malaysia’s Local Mushrooms in Air-Lift Bioreactor

Abstract

Four local mushroom species, viz. Auricularis polytricha, Lentinus edodes, Agrocybe sp and Pleurotus flabellatus were grown under submerged culture and screened for endopolysaccharides. The fermentation was done in 250 ml working volume Erlenmeyer flask and the fermentation curves for all species were established. Pleurotus flabellatus has the highest rate of biomass production at the rate of 0.180 g/L/day, at 10 days hence chosen for further investigation. Two additional media, viz. Mushroom Complete Media (MCM) and Yeast Malt (YM) were selected to be compared with potato extract(PE) media used initially. MCM media produced the highest biomass productivity at the rate of 0.311 g/L/day. Pleurotus flabellatus biomass was extracted using modified Mizuno method and the endopolysaccharide obtained was tested for β -glucan. The yield of β -glucan was 7.70 ± 1.11 g/100g. The polysaccharides were purified using column chromatography to yield four fractions. The fourth fraction F 4 , gave the highest molecular weight at 3.058 × 10 6 Dalton (11.8%) and 1.282 × 10 4 Dalton (88.2%). The mushroom, P. flabbelatus was cultured using air-lift bioreactor, and the highest productivity was obtained at air-flowrate 2 L/min, yielding 2.25 g/L/day. The yield of biomass against substrate used (glucose consumption) Y b/s was 0.78 g/g.