title: Conversion of apple pomace waste to ethanol at industrial relevant conditions.
abstract: Apple pomace samples were evaluated for conversion to ethanol at industrial relevant conditions. Biomass degradation efficiency by commercial enzymes was evaluated at 20 % solid loading for dilute sulfuric acid, calcium oxide, and autoclave without any chemical (control) apple pomace samples. The control and calcium oxide-pretreated pomace provided similar sugar yields, while dilute sulfuric acid pretreatment resulted in reduced sugar yields. The control and calcium oxide-pretreated pomace hydrolysate were fermented to ethanol using a native Saccharomyces cerevisiae yeast strain, producing 38.8 and 36.9 g/L of ethanol, respectively. When control apple pomace sample loading was increased from 20 to 30 %, 57.5 and 50.1 g/L of glucose and fructose was produced, respectively. Lastly, we found that unhydrolyzed solids (UHS) present during fermentation had little effect on ethanol yield, as 53.6 and 53.8 g/L of ethanol were produced with and without UHS, respectively. Overall, ethanol yields were 134 g per kg of dry apple pomace. A complete process mass balance for enzyme hydrolysis and ethanol fermentation is provided in this manuscript. These results show that apple pomace is an excellent feedstock for producing ethanol that could be either used as biofuel or as beverage.
authors.affiliation: Biomass Conversion Research Laboratory (BCRL), Department of Chemical Engineering and Material Science, Michigan State University (MSU), MBI Building, 3900 Collins Road, Lansing, MI, 48910, USA.
authors.forename: Margaret
authors.initials: M
authors.lastname: Magyar
authors.affiliation: Biomass Conversion Research Laboratory (BCRL), Department of Chemical Engineering and Material Science, Michigan State University (MSU), MBI Building, 3900 Collins Road, Lansing, MI, 48910, USA.
authors.forename: Leonardo
authors.initials: L
authors.lastname: da Costa Sousa
authors.affiliation: Biomass Conversion Research Laboratory (BCRL), Department of Chemical Engineering and Material Science, Michigan State University (MSU), MBI Building, 3900 Collins Road, Lansing, MI, 48910, USA.|School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing, 210094, China.
authors.forename: Mingjie
authors.initials: M
authors.lastname: Jin
authors.affiliation: Biomass Conversion Research Laboratory (BCRL), Department of Chemical Engineering and Material Science, Michigan State University (MSU), MBI Building, 3900 Collins Road, Lansing, MI, 48910, USA.
authors.forename: Cory
authors.initials: C
authors.lastname: Sarks
authors.affiliation: Biomass Conversion Research Laboratory (BCRL), Department of Chemical Engineering and Material Science, Michigan State University (MSU), MBI Building, 3900 Collins Road, Lansing, MI, 48910, USA. balan@msu.edu.
authors.forename: Venkatesh
authors.initials: V
authors.lastname: Balan
mesh_terms: D001628:Beverages; D056804:Biofuels / Q000382:microbiology*; D018533:Biomass; D017610:Calcium Compounds / Q000737:chemistry; D000431:Ethanol / Q000378:metabolism*; D005285:Fermentation / Q000502:physiology*; D005947:Glucose / Q000378:metabolism; D027845:Malus / Q000378:metabolism*; D010087:Oxides / Q000737:chemistry; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D013464:Sulfuric Acids / Q000737:chemistry
chemical_list: D056804:Biofuels; D017610:Calcium Compounds; D010087:Oxides; D013464:Sulfuric Acids; D000431:Ethanol; C016538:lime; D005947:Glucose; C033158:sulfuric acid
keywords: Apple pomace; Enzymatic hydrolysis; Ethanol; Microbial fermentation; Pretreatment