Bio-based algal (Chlorella vulgaris) refinery on de-oiled algae biomass cake: A study on biopolymer and biodiesel production

In this study, a novel bio-refinery concept was designed for efficient utilization of de-oiled algae cake as bio-resource for biopolymer (Polyhydroxyalkanoates (PHB)) production and thereby making the biorefinery process more economical and sustainable by completely utilizing the algal biomass without the production of waste algal residues. Algal oil was extracted from Chlorella vulgaris biomass via Bligh and Dyer method for biodiesel production through parabolic solar trough collector. Maximum lipid yield was 27.5 wt% at a temperature of 45 °C with de-oiled cake (DC) yield of 0.37 g. Maximum algal oil conversion efficiency was 89% and 94% for 0.3 wt% of clam shell waste and commercial calcium oxide catalyst at 90 min. After a reaction time of 120 h, the glucose, soluble sugars, xylose, and arabinose in the DC was reduced by 53%, 21%, 63%, and 69% respectively. The maximum PHB yield was 0.41 g PHB/g DC. This study provides additional support for the algal refineries on sustainability and circular usage of algae biomass for production of multiple products. [Display omitted] •Bio-refinery potential of Chlorella vulgaris biomass was explored in this study.•Algal oil of 27.5 wt% and de-oiled cake of 0.37 g was extracted from the biomass.•Solar trough collector resulted conversion efficiency of 89% at 0.3 wt% catalyst.•Polyhydroxyalkanoates (PHB) of 0.41 g was produced from 1 g of de-oiled cake.•After 120 h, sugars in the de-oiled cake were reduced to more than half percent.