Lipid Production from Sugarcane Top Hydrolysate and Crude Glycerol with Rhodosporidiobolus fluvialis Using a Two-Stage Batch-Cultivation Strategy with Separate Optimization of Each Stage

Abstract

Lipids from oleaginous microorganisms, including oleaginous yeasts, are recognized as feedstock for biodiesel production. A production process development of these organisms is necessary to bring lipid feedstock production up to the industrial scale. This study aimed to enhance lipid production of low-cost substrates, namely sugarcane top and biodiesel-derived crude glycerol, by using a two-stage cultivation process with Rhodosporidiobolus fluvialis DMKU-SP314. In the first stage, sugarcane top hydrolysate was used for cell propagation, and in the second stage, cells were suspended in a crude glycerol solution for lipid production. Optimization for high cell mass production in the first stage, and for high lipid production in the second stage, were performed separately using a one-factor-at-a-time methodology together with response surface methodology. Under optimum conditions in the first stage (sugarcane top hydrolysate broth containing; 43.18 g/L total reducing sugars, 2.58 g/L soy bean powder, 0.94 g/L (NH4)2SO4, 0.39 g/L KH2PO4 and 2.5 g/L MgSO4 7H2O, pH 6, 200 rpm, 28 °C and 48 h) and second stage (81.54 g/L crude glycerol, pH 5, 180 rpm, 27 °C and 196 h), a high lipid concentration of 15.85 g/L, a high cell mass of 21.07 g/L and a high lipid content of 73.04% dry cell mass were obtained.

Exploring Yeast Diversity to Produce Lipid-Based Biofuels from Agro-Forestry and Industrial Organic Residues

“…Different combinations of crude glycerol and other carbon sources present in lignocellulosic biomasses or other organic industrial residues were also explored [ 43 , 151 , 157 , 175 , 176 , 177 ]. The addition of cellulosic hydrolysates to crude glycerol improved the lipid production rate of Rhodotorula species.…”

“…Among the aforementioned species, the lipid profile of R. toruloides oils was the closest to the palm oil used for biodiesel [ 157 ]. The strategy of fed-batch cultivation, using sugarcane top hydrolysate as a substrate in the first stage and crude glycerol in the second stage was found to have a strong influence on biomass and lipid production in Rhodosporidiobolus fluvialis DMKU–SP314 [ 175 , 177 ]. Genetically engineered microorganisms are also an alternative to enhance lipid production using low-cost residual substrates.…”