Biomass and lipid production by the yeast Rhodotorula mucilaginosa using cassava wastewater as the substrate

Abstract

Due to elevated and intense industrial activity, thousands of tons of waste are generated every day. One of these wastes, cassava wastewater, is a liquid generated during cassava processing. Thus this study aimed to evaluate the effect of varying the concentration of cassava wastewater on the production of biomass and lipids by the yeast Rhodotorula mucilaginosa . The quantities of biomass produced were 4.1, 6.95 and 5.77 g.L^-1 plus 13.33%, 7.71% and 8.47% of lipids during the cultivations with 50%, 75% and 100% of cassava wastewater, respectively. The synthetic cultivation produced 9.39 g.L^-1 of biomass and 41.92% of lipids. The culture with 100% cassava wastewater presented the best conversion efficiency coefficient of total reducing sugars to biomass and the synthetic culture, without cassava wastewater, the best coefficient for lipids. Thus cassava wastewater was shown to be a potential substrate for the growth of the yeast Rhodotorula mucilaginosa and for lipid production, and this production could be further optimized.

Keywords:
Agro-industrial waste; Culture; Microbial lipids; C/N ratio; Reducing sugars; Glucose