title: Analysis and optimization of triacylglycerol synthesis in novel oleaginous Rhodococcus and Streptomyces strains isolated from desert soil.
abstract: As oleaginous microorganisms represent an upcoming novel feedstock for the biotechnological production of lipids or lipid-derived biofuels, we searched for novel, lipid-producing strains in desert soil. This was encouraged by the hypothesis that neutral lipids represent an ideal storage compound, especially under arid conditions, as several animals are known to outlast long periods in absence of drinking water by metabolizing their body fat. Ten lipid-accumulating bacterial strains, affiliated to the genera Bacillus, Cupriavidus, Nocardia, Rhodococcus and Streptomyces, were isolated from arid desert soil due to their ability to synthesize poly(β-hydroxybutyrate), triacylglycerols or wax esters. Particularly two Streptomyces sp. strains and one Rhodococcus sp. strain accumulate significant amounts of TAG under storage conditions under optimized cultivation conditions. Rhodococcus sp. A27 and Streptomyces sp. G49 synthesized approx. 30% (w/w) fatty acids from fructose or cellobiose, respectively, while Streptomyces isolate G25 reached a cellular fatty acid content of nearly 50% (w/w) when cultivated with cellobiose. The stored triacylglycerols were composed of 30-40% branched fatty acids, such as anteiso-pentadecanoic or iso-hexadecanoic acid. To date, this represents by far the highest lipid content described for streptomycetes. A biotechnological production of such lipids using (hemi)cellulose-derived raw material could be used to obtain sustainable biodiesel with a high proportion of branched-chain fatty acids to improve its cold-flow properties and oxidative stability.
authors.affiliation: Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität Münster, D-48149 Münster, Germany.
authors.forename: Annika
authors.initials: A
authors.lastname: Röttig
authors.affiliation: Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität Münster, D-48149 Münster, Germany.
authors.forename: Philippa
authors.initials: P
authors.lastname: Hauschild
authors.affiliation: Environmental Sciences Department, Faculty of Meteorology, Environment and Arid Land Agriculture, King Abdulaziz University, 21589 Jeddah, Saudi Arabia.
authors.forename: Mohamed H
authors.initials: MH
authors.lastname: Madkour
authors.affiliation: Environmental Sciences Department, Faculty of Meteorology, Environment and Arid Land Agriculture, King Abdulaziz University, 21589 Jeddah, Saudi Arabia.
authors.forename: Ahmed M
authors.initials: AM
authors.lastname: Al-Ansari
authors.affiliation: Environmental Sciences Department, Faculty of Meteorology, Environment and Arid Land Agriculture, King Abdulaziz University, 21589 Jeddah, Saudi Arabia.
authors.forename: Naief H
authors.initials: NH
authors.lastname: Almakishah
authors.affiliation: Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität Münster, D-48149 Münster, Germany; Environmental Sciences Department, Faculty of Meteorology, Environment and Arid Land Agriculture, King Abdulaziz University, 21589 Jeddah, Saudi Arabia. Electronic address: steinbu@uni-muenster.de.
authors.forename: Alexander
authors.initials: A
authors.lastname: Steinbüchel
mesh_terms: D056804:Biofuels; D005227:Fatty Acids; D012240:Rhodococcus / Q000737:chemistry / Q000145:classification / Q000302:isolation & purification*; D012988:Soil Microbiology; D013302:Streptomyces / Q000737:chemistry / Q000145:classification / Q000302:isolation & purification*; D014280:Triglycerides / Q000378:metabolism*
chemical_list: D056804:Biofuels; D005227:Fatty Acids; D014280:Triglycerides
keywords: Branched-chain biodiesel; Desert soil; Oleaginous microorganisms; Streptomyces; Triacylglycerol