title: Water reclamation and value-added animal feed from corn-ethanol stillage by fungal processing.
abstract: Rhizopus oligosporus was cultivated on thin stillage from a dry-grind corn ethanol plant. The aim of the research was to develop a process to replace the current energy-intensive flash evaporation and make use of this nutrient-rich stream to create a new co-product in the form of protein-rich biomass. Batch experiments in 5- and 50-L stirred bioreactors showed prolific fungal growth under non-sterile conditions. COD, suspended solids, glycerol, and organic acids removals, critical for in-plant water reuse, reached ca. 80%, 98%, 100% and 100%, respectively, within 5 d of fungal inoculation, enabling effluent recycle as process water. R. oligosporus contains 2% lysine, good levels of other essential amino acids, and 43% crude protein - a highly nutritious livestock feed. Avoiding water evaporation from thin stillage would furthermore save substantial energy inputs on corn ethanol plants.
authors.affiliation: Department of Civil, Construction, and Environmental Engineering, Iowa State University, Ames, IA 50011, USA; Biorenewable Resources and Technology Program, Iowa State University, Ames, IA 50011, USA.
authors.forename: M L
authors.initials: ML
authors.lastname: Rasmussen
authors.forename: S K
authors.initials: SK
authors.lastname: Khanal
authors.forename: A L
authors.initials: AL
authors.lastname: Pometto
authors.forename: J Hans
authors.initials: JH
authors.lastname: van Leeuwen
mesh_terms: D019342:Acetic Acid / Q000378:metabolism; D000596:Amino Acids / Q000378:metabolism; D000821:Animal Feed; D057919:Biological Oxygen Demand Analysis; D018533:Biomass; D000431:Ethanol / Q000737:chemistry*; D005656:Fungal Proteins / Q000378:metabolism; D005990:Glycerol / Q000302:isolation & purification; D019344:Lactic Acid / Q000378:metabolism; D009821:Oils; D009930:Organic Chemicals / Q000302:isolation & purification; D010100:Oxygen / Q000032:analysis; D012233:Rhizopus / Q000254:growth & development / Q000378:metabolism*; D012995:Solubility; D014867:Water / Q000737:chemistry*; D003313:Zea mays / Q000737:chemistry*
chemical_list: D000596:Amino Acids; D005656:Fungal Proteins; D009821:Oils; D009930:Organic Chemicals; D014867:Water; D019344:Lactic Acid; D000431:Ethanol; D005990:Glycerol; D019342:Acetic Acid; D010100:Oxygen
keywords: Animal feed; Ethanol; Fungal process; Thin stillage; Water reuse