title: Bioconversion of crude glycerol to glycolipids in Ustilago maydis.
abstract: Ustilago maydis is known to produce glycolipid-type biosurfactants. Here, we show that U. maydis is able to efficiently convert biodiesel-derived crude glycerol to glycolipids. We have optimized the medium composition and environmental factors for bioconversion of crude glycerol to glycolipids. The synthetic medium (MinCG) contains 50 g L(-1) crude glycerol and 20.3 mg L(-1) ammonium citrate as the carbon and nitrogen sources, respectively. The supplementation of trace amount of amino acids, Group-B vitamins and precursors of glycolipids, mannose and erythritol, also improved the final yield. At pH 4.0 and 30°C, 32.1 g L(-1) total glycolipids was produced in a 8.2-day fed-batch bioprocess. Methanol at 2% or above severely inhibited cell growth and production of glycolipids. Our results suggest that U. maydis is an excellent host for the bioconversion of crude glycerol to value-added products.
authors.affiliation: Biomaterials and Biocatalysts Group, Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore 117604, Singapore.
authors.forename: Yanbin
authors.initials: Y
authors.lastname: Liu
authors.forename: Chong Mei John
authors.initials: CM
authors.lastname: Koh
authors.forename: Lianghui
authors.initials: L
authors.lastname: Ji
mesh_terms: D001709:Biotechnology / Q000379:methods*; D002244:Carbon / Q000737:chemistry; D019343:Citric Acid / Q000737:chemistry; D003470:Culture Media; D005227:Fatty Acids / Q000737:chemistry; D005285:Fermentation; D005990:Glycerol / Q000737:chemistry*; D006017:Glycolipids / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D000432:Methanol / Q000737:chemistry; D009584:Nitrogen / Q000737:chemistry; D000644:Quaternary Ammonium Compounds / Q000737:chemistry; D013501:Surface-Active Agents / Q000737:chemistry; D013696:Temperature; D013997:Time Factors; D014588:Ustilago / Q000378:metabolism*
chemical_list: D003470:Culture Media; D005227:Fatty Acids; D006017:Glycolipids; D000644:Quaternary Ammonium Compounds; D013501:Surface-Active Agents; D019343:Citric Acid; D002244:Carbon; C481046:ammonium citrate; D009584:Nitrogen; D005990:Glycerol; D000432:Methanol