title: Formulation of fermentation media from flour-rich waste streams for microbial lipid production by Lipomyces starkeyi.
abstract: Flour-rich waste (FRW) and by-product streams generated by bakery, confectionery and wheat milling plants could be employed as the sole raw materials for generic fermentation media production, suitable for microbial oil synthesis. Wheat milling by-products were used in solid state fermentations (SSF) of Aspergillus awamori for the production of crude enzymes, mainly glucoamylase and protease. Enzyme-rich SSF solids were subsequently employed for hydrolysis of FRW streams into nutrient-rich fermentation media. Batch hydrolytic experiments using FRW concentrations up to 205 g/L resulted in higher than 90% (w/w) starch to glucose conversion yields and 40% (w/w) total Kjeldahl nitrogen to free amino nitrogen conversion yields. Starch to glucose conversion yields of 98.2, 86.1 and 73.4% (w/w) were achieved when initial FRW concentrations of 235, 300 and 350 g/L were employed in fed-batch hydrolytic experiments, respectively. Crude hydrolysates were used as fermentation media in shake flask cultures with the oleaginous yeast Lipomyces starkeyi DSM 70296 reaching a total dry weight of 30.5 g/L with a microbial oil content of 40.4% (w/w), higher than that achieved in synthetic media. Fed-batch bioreactor cultures led to a total dry weight of 109.8 g/L with a microbial oil content of 57.8% (w/w) and productivity of 0.4 g/L/h.
authors.affiliation: Department of Food Science and Human Nutrition, Agricultural University of Athens, 75 Iera Odos, 11855 Athens, Greece.
authors.forename: Sofia
authors.initials: S
authors.lastname: Tsakona
authors.affiliation: Department of Food Science and Human Nutrition, Agricultural University of Athens, 75 Iera Odos, 11855 Athens, Greece.
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Kopsahelis
authors.affiliation: Department of Food and Nutritional Sciences, University of Reading, Whiteknights, Reading RG6 6AD, UK.
authors.forename: Afroditi
authors.initials: A
authors.lastname: Chatzifragkou
authors.affiliation: Department of Food Science and Human Nutrition, Agricultural University of Athens, 75 Iera Odos, 11855 Athens, Greece.
authors.forename: Seraphim
authors.initials: S
authors.lastname: Papanikolaou
authors.affiliation: Department of Chemical Engineering, University of Patras, 26504 Patras, Rio, Greece.
authors.forename: Ioannis K
authors.initials: IK
authors.lastname: Kookos
authors.affiliation: Department of Food Science and Human Nutrition, Agricultural University of Athens, 75 Iera Odos, 11855 Athens, Greece. Electronic address: akoutinas@aua.gr.
authors.forename: Apostolis A
authors.initials: AA
authors.lastname: Koutinas
mesh_terms: D001709:Biotechnology; D005285:Fermentation / Q000502:physiology; D008055:Lipids / Q000502:physiology; D055160:Lipomyces / Q000378:metabolism*
chemical_list: D008055:Lipids
keywords: Enzymatic hydrolysis; Food waste valorisation; Lipomyces starkeyi; Microbial oil; Solid state fermentation