Abstract
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, HPAECPAD,
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 mol1
) 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 L1 and accumulated
42.1% in oils based on cell dry weight after 48 h.