Main content area

Conversion of corn stover alkaline pre-treatment waste streams into biodiesel via Rhodococci

Le, Rosemary K., Wells Jr., Tyrone, Das, Parthapratim, Meng, Xianzhi, Stoklosa, Ryan J., Bhalla, Aditya, Hodge, David B., Yuan, Joshua S., Ragauskas, Arthur J.
RSC advances 2017 v.7 no.7 pp. 4108-4115
Rhodococcus jostii, Rhodococcus opacus, bacteria, biodiesel, bioethanol, biorefining, biotransformation, corn stover, feedstocks, fermentation, glucose, lignin, lipids, molecular weight, oils, solubilization, viability
The bioconversion of second-generation cellulosic ethanol waste streams into biodiesel via oleaginous bacteria is a novel optimization strategy for biorefineries with substantial potential for rapid development. In this study, one- and two-stage alkali/alkali-peroxide pretreatment waste streams of corn stover were separately implemented as feedstocks in 96 h batch reactor fermentations with wild-type Rhodococcus opacus PD 630, R. opacus DSM 1069, and R. jostii DSM 44719ᵀ. Here we show using ³¹P-NMR, HPAEC-PAD, and SEC analyses, that the more rigorous and chemically-efficient two-stage chemical pretreatment effluent provided higher concentrations of solubilized glucose and lower molecular weight (∼70–300 g mol⁻¹) lignin degradation products thereby enabling improved cellular density, viability, and oleaginicity in each respective strain. The most significant yields were by R. opacus PD 630, which converted 6.2% of organic content with a maximal total lipid production of 1.3 g L⁻¹ and accumulated 42.1% in oils based on cell dry weight after 48 h.