Utilization of inulin-containing waste in industrial fermentations to produce biofuels and bio-based chemicals.
Inulins are polysaccharides that belong to an important class of carbohydrates known as fructans and are used by many plants as a means of storing energy. Inulins contain 20 to several thousand fructose units joined by β-2,1 glycosidic bonds, typically with a terminal glucose unit. Plants with high concentrations of inulin include: agave, asparagus, coffee, chicory, dahlia, dandelion, garlic, globe artichoke, Jerusalem artichoke, jicama, onion, wild yam, and yacón. To utilize inulin as its carbon and energy source directly, a microorganism requires an extracellular inulinase to hydrolyze the glycosidic bonds to release fermentable monosaccharides. Inulinase is produced by many microorganisms, including species of Aspergillus, Kluyveromyces, Penicillium, and Pseudomonas. We review various inulinase-producing microorganisms and inulin feedstocks with potential for industrial application as well as biotechnological efforts underway to develop sustainable practices for the disposal of residues from processing inulin-containing crops. A multi-stage biorefinery concept is proposed to convert cellulosic and inulin-containing waste produced at crop processing operations to valuable biofuels and bioproducts using Kluyveromyces marxianus, Yarrowia lipolytica, Rhodotorula glutinis, and Saccharomyces cerevisiae as well as thermochemical treatments.
Renewable Product Technology Research Unit, United States Department of Agriculture (USDA), Agricultural Research Service (ARS), National Center for Agricultural Utilization Research (NCAUR), 1815 North University Street, Peoria, IL, 61604, USA. stephen.hughes@ars.usda.gov.
Stephen R
SR
Hughes
Bioenergy Research Unit, USDA, ARS, NCAUR, 1815 North University Street, Peoria, IL, 61604, USA.
Nasib
N
Qureshi
National Coffee Research Centre (Cenicafe), National Federation of Coffee Growers of Colombia (FNC), Cenicafé Planalto Km 4 vía Antigua Chinchiná, Manizales, Caldas, Colombia.
Juan Carlos
JC
López-Núñez
Department of Chemistry, Illinois State University, Normal, IL, 61790, USA.
Marjorie A
MA
Jones
Department of Chemistry, Illinois State University, Normal, IL, 61790, USA.
Joshua M
JM
Jarodsky
National Coffee Research Centre (Cenicafe), National Federation of Coffee Growers of Colombia (FNC), Cenicafé Planalto Km 4 vía Antigua Chinchiná, Manizales, Caldas, Colombia.
Luz Ángela
LÁ
Galindo-Leva
Renewable Product Technology Research Unit, United States Department of Agriculture (USDA), Agricultural Research Service (ARS), National Center for Agricultural Utilization Research (NCAUR), 1815 North University Street, Peoria, IL, 61604, USA.
Mitchell R
MR
Lindquist
D001230:Aspergillus / Q000201:enzymology; D001419:Bacteria / Q000201:enzymology* / Q000254:growth & development; D001426:Bacterial Proteins / Q000378:metabolism; D056804:Biofuels / Q000382:microbiology*; D005285:Fermentation; D005656:Fungal Proteins / Q000378:metabolism; D005658:Fungi / Q000201:enzymology / Q000254:growth & development*; D006026:Glycoside Hydrolases / Q000378:metabolism*; D007220:Industrial Waste; D007444:Inulin / Q000378:metabolism*; D007716:Kluyveromyces / Q000201:enzymology; D010407:Penicillium / Q000201:enzymology; D010944:Plants / Q000378:metabolism*; D011549:Pseudomonas / Q000201:enzymology
D001426:Bacterial Proteins; D056804:Biofuels; D005656:Fungal Proteins; D007220:Industrial Waste; D007444:Inulin; D006026:Glycoside Hydrolases; C023086:inulinase
Bioethanol; Fructose; Inulin bioprocessing; Inulin waste; Inulinase-producing microorganisms