Microbial lipid production by oleaginous yeasts on Laminaria residue hydrolysates

Abstract

Laminaria residues are major wastes during the production of alginate, mannitol and iodine by the kelp industry. To explore the capability of using Laminaria residues for microbial lipid production, here we developed an effective hydrolysis process to prepare Laminaria residue hydrolysates (LRH). Ten oleaginous yeast strains were then screened on agar plates using LRH as the sole nutrient sources. Two strains, Rhodosporidium toruloides Y4 and Rhodotorula glutinis AS 2.107, were found to use LRH for lipid production when phosphorus was removed, and lipid yields and cellular lipid contents reached 0.16 g g⁻¹ total reducing sugar (TRS) and 37.6%, and 0.07 g g⁻¹ TRS and 22.2%, respectively. The lipid products had similar fatty acid composition profiles to those of vegetable oils. Our results demonstrate the potential of integrating lipid-based biofuel production and the kelp industry, which should facilitate more efficient utilization of macroalgae resources such as Laminaria and related marine biomass.