Obtenção de lipídios por processo biotecnológico utilizando a manipueira como substrato

Abstract

Due of the high and steady industrial activity, every day thousands of tons of waste are generated, many of these aren’t used, and discarded directly into the environment, without any prior treatment, which may cause serious environmental impacts. Knowing that, this research aimed to evaluate the effects of the components of the culture medium on the biomass and lipids produced using cassava wastewater and the yeast Rhodotorula mucilaginosa CCT 7668. Was verified the influence of medium components and of the concentration of cassava on the production of biomass and lipids. R. mucilaginosa cells were cultured in YMA medium and inoculated in Erlenmeyer flasks with 20% cassava wastewater supplemented with glucose, magnesium sulfate, potassium phosphate and yeast extract. In the second culture, was used 50, 75 and 100% of cassava wastewater with fixed concentration 3 g.L-1 yeast extract. The cultivation was carried in a rotary incubator subjected to a temperature of 30 °C, under constant agitation at 200 rpm for 120 hours. During predefined time intervals, aliquots were removed of the medium for biomass and lipids measurement. The cassava wastewater showed 92.38% of humidity, 30.2 g.L-1 of reducing sugars, 51 g L-1 of total sugars, 1.17% of protein and 0.53% of ash, titratable acidity 3.20 ( NaOH.100 meq ml-1), total soluble solids of 7,0 ºBrix and pH equivalent to 5.26. In the cultivation using a medium containing 20 % de cassava wastewater, the maximum biomass was equivalent to 7.49 g.L-1, 96 h after the inoculum, and the same time interval were produced 2,25 g.L-1 de lipids, equivalent 30% of the lipids in dry biomass. Were produced 4,10, 6,95, 5,77 g.L-1 of biomass and 13,33, 7,71 and 8,47% of lipids in the cultivations with 50, 75 and 100% of cassava wastewater, respectively. The culture with syntethic medium produced 9,39 g.L-1 of biomass and 41,92 % of lipids. The experiment with 100% manipueira showed the best yield coefficient conversion of total reducing sugars in biomass (0.5188 gg-1) and the culture with 50%, the best performance in the production of lipids (0.0049 gg-1). Cassava wastewater was observed as a potential substrate for the production of lipids by Rhodotorula mucilaginosa and can be used in a fermentation processes, adding value to the waste and minimizing possible environmental impacts by improper discard.