Process for Preparing Value-Added Products from Microalgae Using Textile Effluent through a Biorefinery Approach

A model was designed for effective utilization of textile effluent as the nutrient medium for the production of high-value products from Chlorella variabilis through a greener approach. Biomass productivity of 74.96 +/- 2.62 g/(m(2)/d) with lipid yield of 20.1 +/- 2.2% (wrt dry biomass) was obtained using textile effluent as the nutrient source. A novel integrated process is developed based on detergent (sodium dodecyl sulfate) hydrolysis to convert the carbohydrates present in microalgal biomass to reducing sugars for microbial fermentation, while making available lipids for downstream processing of gamma-linolenic acid, leaving the protein rich fragment behind. Our experimental data showed that from 495 g of microalgal biomass, 109.4 g total lipids was extracted containing 34.65 g gamma-linolenic acid, and 1.3 g pure epsilon-polylysine from 36.68 g of reducing sugars. A two-step efficient green process was developed for recovering e-polylysine using ethylammonium nitrate having 74% recovery. In addition to value-added products, CSIR-CSMCRI's Chlorella variabilis (ATCC PTA 12198) can remediate 100% of aluminum, 82.72% boron, 45.66% calcium, 100% cobalt, 14.5% potassium, 0.1% magnesium, 42.18% sodium, 100% nickel, and 100% iron. A total decrease of 78.17% total phosphate and 25.22% total inorganic phosphate with respect to total phosphate present in the effluent was observed.