title: Physiological and genetic differences amongst Rhodococcus species for using glycerol as a source for growth and triacylglycerol production.
abstract: We analysed the ability of five different rhodococcal species to grow and produce triacylglycerols (TAGs) from glycerol, the main byproduct of biodiesel production. Rhodococcus fascians and Rhodococcus erythropolis grew fast on glycerol, whereas Rhodococcus opacus and Rhodococcus jostii exhibited a prolonged lag phase of several days before growing. Rhodococcus equi only exhibited poor growth on glycerol. R. erythropolis DSMZ 43060 and R. fascians F7 produced 3.9-4.3 g cell biomass l(-1) and 28.4-44.6% cellular dry weight (CDW) of TAGs after 6 days of incubation; whereas R. opacus PD630 and R. jostii RHA1 produced 2.5-3.8 g cell biomass l(-1) and 28.3-38.4% CDW of TAGs after 17 days of growth on glycerol. Genomic analyses revealed two different sets of genes for glycerol uptake and degradation (here named clusters 1 and 2) amongst rhodococci. Those species that possessed cluster 1 (glpFK1D1) (R. fascians and R. erythropolis) exhibited fast growth and lipid accumulation, whereas those that possessed cluster 2 (glpK2D2) (R. opacus, R. jostii and R. equi) exhibited delayed growth and lipid accumulation during cultivation on glycerol. Three glycerol-negative strains were complemented for their ability to grow and produce TAGs by heterologous expression of glpK2 from R. opacus PD630. In addition, we significantly reduced the extension of the lag phase and improved glycerol assimilation and oil production of R. opacus PD630 when expressing glpK1D1 from R. fascians. The results demonstrated that rhodococci are a flexible and amenable biological system for further biotechnological applications based on the reutilization of glycerol.
authors.affiliation: Centro Regional de Investigación y Desarrollo Científico Tecnológico, Facultad de Ciencias Naturales,Universidad Nacional de la Patagonia San Juan Bosco y CIT-CHUBUT CONICET, Km 4-Ciudad Universitaria, 9000 Comodoro Rivadavia (Chubut), Argentina.|Oil m&s, Avenida Hipólito Yrigoyen 4250, 9000 Comodoro Rivadavia (Chubut), Argentina.
authors.forename: O Marisa
authors.initials: OM
authors.lastname: Herrero
authors.affiliation: Departamento de Biología Molecular e Instituto de Biomedicina y Biotecnología de Cantabria,Universidad de Cantabria-Consejo Superior de Investigaciones Científicas-SODERCAN, Calle Albert Einstein 22, 39011 Santander,Spain.
authors.forename: Gabriel
authors.initials: G
authors.lastname: Moncalián
authors.affiliation: Centro Regional de Investigación y Desarrollo Científico Tecnológico, Facultad de Ciencias Naturales,Universidad Nacional de la Patagonia San Juan Bosco y CIT-CHUBUT CONICET, Km 4-Ciudad Universitaria, 9000 Comodoro Rivadavia (Chubut), Argentina.
authors.forename: Héctor M
authors.initials: HM
authors.lastname: Alvarez
mesh_terms: D056804:Biofuels; D001692:Biological Transport / Q000235:genetics*; D019149:Bioreactors / Q000382:microbiology; D005227:Fatty Acids / Q000096:biosynthesis*; D005818:Genetic Engineering; D005990:Glycerol / Q000378:metabolism*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012240:Rhodococcus / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*; D014280:Triglycerides / Q000096:biosynthesis*
chemical_list: D056804:Biofuels; D005227:Fatty Acids; D012336:RNA, Ribosomal, 16S; D014280:Triglycerides; D005990:Glycerol