Co-production of microbial lipids and biosurfactant from waste office paper hydrolysate using a novel strain Bacillus velezensis ASN1

Microbial lipids and biosurfactant were successfully co-produced using waste office paper (WOP) as a substrate using a novel strain Bacillus velezensis ASN1. WOP was pretreated with 1% (v/v) H₂SO₄ and enzymatically hydrolyzed using cellulase (37 FPU/g solid) and β-glucosidase (25 CBU/g solid). The total sugar yield was 21.28 g/L at 120 h and the percentage of hydrolysis was 89.07%. The obtained WOP hydrolysate was used as a substrate for the co-production of microbial lipids and biosurfactant. The best nitrogen source and carbon to nitrogen ratio for lipid production was found to be ammonium chloride and C/N 20, respectively. A lipid content of 31% was obtained with a fatty acid profile of myristic, pentadecanoic, palmitic, and stearic acid methyl esters. The crude biosurfactant was extracted by acid precipitation of the supernatant yielded 0.818 g/L and was characterized using NMR, FTIR, and LC–MS, and proved as lipopeptides. The biorefinery approach of co-producing of microbial lipid and biosurfactant using waste paper would reduce the production cost of biodiesel.