Optimization of enzymatic hydrolysis of cellulosic fraction obtained from stranded driftwood feedstocks for lipid production by Solicoccozyma terricola

Abstract

Stranded driftwood feedstocks may represent, after pretreatment with steam explosion and enzymatic hydrolysis, a cheap C-source for producing biochemicals and biofuels using oleaginous yeasts. The hydrolysis was optimized using a response surface methodology (RSM). The solid loading (SL) and the dosage of enzyme cocktail (ED) were variated following a central composite design (CCD) aimed at optimizing the conversion of carbohydrates into lipids (YL) by the yeast Solicoccozyma terricola DBVPG 5870.A second-order polynomial equation was computed for describing the effect of ED and SL on YL.The best combination (ED = 3.10%; SL = 22.07%) for releasing the optimal concentration of carbohydrates which gave the highest predicted YL (27.32%) was then validated by a new hydrolysis. The resulting value of YL (25.26%) was close to the theoretical maximum value.Interestingly, fatty acid profile achieved under the optimized conditions was similar to that reported for palm oil. Keywords: Stranded driftwood feedstocks, Solicoccozyma terricola, Enzymatic hydrolysis, Yeast biochemicals and biofuels, Response surface methodology