Biological conversion of the aqueous wastes from hydrothermal liquefaction of algae and pine wood by Rhodococci

In this study, R. opacus PD630, R. jostii RHA1, R. jostii RHA1 VanA , and their co-culture were employed to convert hydrothermal liquefaction aqueous waste (HTLAW) into lipids. After 11 days, the COD reduction of algal-HTLAW reached 93.4% and 92.7% by R. jostii RHA1 and its mutant VanA , respectively. Woody-HTLAW promoted lipid accumulation of 0.43 g lipid/g cell dry weight in R. opacus PD630 cells. Additionally, the total number of chemicals in HTLAW decreased by over 1/3 after 7 days of coculture, and 0.10 g/L and 0.46 g/L lipids were incrementally accumulated in the cellular mass during the fermentation of wood-and algal-HTLAW, respectively. The GC-MS data supported that different metabolism pathways were followed when these Rhodococci strains degraded algae-and woody-HTLAW. These results indicated promising potential of bioconversion of under-utilized carbon and toxic compounds in HTLAW into useful products by selected Rhodococci. (C) 2016 Elsevier Ltd. All rights reserved.