Optimization of macroelement concentrations, pH and osmolarity for triacylglycerol accumulation in Rhodococcus opacus strain PD630

Abstract

The refinement of biodiesel or renewable diesel from bacterial lipids has a great potential to make a contribution for energy production in the future. This study provides new data concerning suitable nutrient concentrations for cultivation of the Gram-positive Rhodococcus opacus PD630, which is able to accumulate large amounts of lipids during nitrogen limitation. Enhanced concentrations of magnesium have been shown to increase the final optical density and the lipid content of the cells. Elevated phosphate concentrations slowed down the onset of the accumulation phase, without a clear effect on the final optical density and the cell’s lipid content. A robust growth of R. opacus was possible in the presence of ammonium concentrations of up to 1.4 g l-1 and sucrose concentrations of up to 240 g l-1, with an optimum regarding growth and lipid storage observed in the range of 0.2 to 0.4 g l-1 ammonium and 20 to 40 g l-1 sucrose, respectively. Moreover, R. opacus showed tolerance to high salt concentrations.

Bacterial lipid droplets bind to DNA via an intermediary protein that enhances survival under stress

“…Determining the physiological function of this binding was our next goal. Previous studies have demonstrated that LD formation and TAG content are increased when bacteria are cultured under low nitrogen conditions 27 . Thus, we hypothesized that LDs might contribute to protection of the bacterium from certain stress conditions.…”

Valorization of lubricant-based wastewater for bacterial neutral lipids production: Growth-linked biosynthesis

“…In uncontrolled experiments (shake flask) the dissolved oxygen was not monitored but the pH was observed to decrease from 7.5 to 5, with the growth (doubling times higher than 20 h). The alteration in pH is known to affect negatively fatty acid (FA) production (Janßen et al, 2013). FA production is an intermediate step between the hydrocarbons uptake and either the respiration or the biosynthesis (Wentzel et al, 2007).…”

Statistical design and optimization of single cell oil production from sugarcane bagasse hydrolysate by an oleaginous yeast Rhodotorula sp. IIP-33 using response surface methodology

“…Yeast extract was a rich source of vitamins and promoted cell growth and proliferation (Dasgupta et al 2013 ). Elevated levels of magnesium enhanced accumulation of lipid by promoting acetyl CoA carboxylase enzyme activity (Janβen et al 2013 ). pH primarily affected lipid content and lipid quality.…”