Comparative evaluation of chemical and enzymatic saccharification of mixotrophically grown de-oiled microalgal biomass for reducing sugar production.

•De-oiled biomass of mixotrophically grown microalgae is rich in carbohydrate.•Chemical hydrolysis yield 37% saccharification based on residual biomass.•Enzymatic hydrolysis using Viscozyme L results in 43.44% saccharification yield.•Fed-batch enzymatic hydrolysis resulted in highest reducing sugar yield.•Microalgal hydrolysate is efficiently utilized by yeast for ethanol fermentation.