title: Organic fraction of municipal solid waste as a suitable feedstock for the production of lipid by oleaginous yeast Cryptococcus aerius.
abstract: The detoxified pre-hydrolysate and enzymatic hydrolysate of OFMSW were used as substrates for lipid production by Cryptococcus aerius. Factorial experimental designs were employed for the optimization of dilute acid pre-hydrolysis, detoxification by over-liming, enzymatic hydrolysis, and lipid production. OFMSW pre-hydrolysis with 3% H2SO4 for 45 min was found to be the optimal treatment, resulted in total sugar concentration of 65.5 g/L (32.8% yield, based on grams of total reducing sugar per gram of OFMSW). The optimal detoxification conditions of the pre-hydrolysate by over-liming was incubation at 30 °C and pH 11 for 24h, resulted in the reduction of total nitrogen, total phenolic compounds, and furans by 51.3%, 45.1%, and 100%, respectively. The residual solid was subjected to enzymatic hydrolysis, and the highest sugar concentration of 30.5 g/L was obtained. At optimal conditions, the yeast cultivation on the detoxified pre-hydrolysate and enzymatic hydrolysate resulted in the lipid production of 3.9 g/L (12.8% yield, based on g lipid per g consumed sugar) and 4.3g/L (17.1% yield, based on g lipid per g consumed sugar), respectively. The elemental analysis showed the presence of heavy metals including iron (925 mg/l), zinc (59 mg/l), lead (4.7 mg/l), and nickel (3.5mg/l) in the pre-hydrolysate, which were significantly reduced by the over-liming detoxification.
authors.affiliation: Department of Microbiology, Faculty of Sciences, University of Isfahan, Isfahan, Iran.
authors.forename: Hossein
authors.initials: H
authors.lastname: Ghanavati
authors.affiliation: Department of Microbiology, Faculty of Sciences, University of Isfahan, Isfahan, Iran. Electronic address: I.nahvi@sci.ui.ac.ir.
authors.forename: Iraj
authors.initials: I
authors.lastname: Nahvi
authors.affiliation: Department of Chemical Engineering, Isfahan University of Technology, Isfahan 84156-83111, Iran; Industrial Biotechnology Group, Institute of Biotechnology and Bioengineering, Isfahan University of Technology, Isfahan 84156-83111, Iran.
authors.forename: Keikhosro
authors.initials: K
authors.lastname: Karimi
mesh_terms: D003454:Cryptococcus / Q000254:growth & development / Q000378:metabolism*; D005735:Garbage; D007218:Industrial Microbiology / Q000379:methods*; D050356:Lipid Metabolism; D008055:Lipids / Q000032:analysis / Q000737:chemistry; D062611:Solid Waste / Q000032:analysis*
chemical_list: D008055:Lipids; D062611:Solid Waste
keywords: Detoxification; Dilute acid pre-hydrolysate; Enzymatic hydrolysate; Lipid; Organic fraction of municipal solid waste; Yeast fermentation