Fruit residues as substrates for single-cell oil production by Rhodococcus species: physiology and genomics of carbohydrate catabolism

AbstractStrains belonging toR. opacus,R. jostii,R. fascians,R. erythropolis andR. equi exhibited differential ability to grow and produce lipids from fruit residues (grape marc and apple pomace), as well as single carbohydrates, such as glucose, gluconate, fructose and sucrose. The oleaginous species,R. opacus (strains PD630 and MR22) andR. jostii RHA1, produced higher yields of biomass (5.1 –5.6 g L−1) and lipids (38 –44% of CDW) from apple juice wastes, in comparison toR. erythropolis DSM43060,R. fascians F7 andR. equi ATCC6939 (4.1 –4.3 g L−1 and less than 10% CDW of lipids). The production of cellular biomass and lipids were also higher inR. opacus andR. jostii (6.8 –7.2 g L−1 and 33.9 –36.5% of CDW of lipids) compared toR. erythropolis,R. fascians, andR. equi (3.0 –3.6 g L−1 and less than 10% CDW of lipids), during cultivation of cells on wine grape waste. A genome-wide bioinformatic analysis of rhodococci indicated that oleaginous species possess a complete set of genes/proteins necessary for the efficient utilization of carbohydrates, whereas genomes from non-oleaginous rhodococcal strains lack relevant genes coding for transporters and/or enzymes for the uptake, catabolism and assimilation of carbohydrates, such asgntP,glcP,edd,eda, among others. Results of this study highlight the potential use of the oleaginous rhodococcal species to convert sugar-rich agro-industrial wastes, such as apple pomace and grape marc, into single-cell oils.
Source: World Journal of Microbiology and Biotechnology - Category: Microbiology Source Type: research