Submitted to: Biomass and Bioenergy
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/7/2016
Publication Date: 10/17/2016
Publication URL: https://handle.nal.usda.gov/10113/5574038
Citation: Leathers, T.D., Nunnally, M.S., Stanley, A.M., Rich, J.O. 2016. Utilization of corn fiber for production of schizophyllan. Biomass and Bioenergy. 95:132-136.

Interpretive Summary: In this research, conditions were optimized for production of the valuable biopolymer, schizophyllan, from corn fiber. Utilization of biomass substrates could provide a value-added product from agricultural residues such as corn fiber, in support of the integrated biorefinery concept. Integrated biorefineries will convert biomass substrates to a variety of value-added bioproducts, such as schizophyllan. In previous studies, DDGS, an abundant coproduct of dry grind fuel ethanol production, was identified as a promising biomass substrate for production of schizophyllan. We discovered optimal production conditions for conversion of corn fiber to schizophyllan and conducted physical characterizations of the biopolymer. This work provides a potential new value-added bioproduct for integrated biorefineries of the future.

Technical Abstract: Corn fiber is an abundant lignocellulosic biomass resource produced during the wet milling of corn. Although corn fiber is recalcitrant to enzymatic digestion, the fungus Schizophyllum commune was able to directly utilize corn fiber for production of the valuable bioproduct, schizophyllan. Schizophyllan is a biopolymer composed entirely of glucose, with a ß-1,3-linked backbone and single ß-1,6-linked glucose side chains at every third residue. Schizophyllan is being developed for bulk biomaterial applications, such as in enhanced oil recovery and as a component of biolubricants. S. commune strain ATCC 38548 produced up to 6.8 ± 0.2 g schizophyllan/L when grown in malt extract medium containing 1.0% untreated corn fiber in place of glucose. Pretreatment of corn fiber with alkaline hydrogen peroxide enhanced yields of schizophyllan. Corn steep liquor at 5% (v/v) could replace malt extract as a nitrogen source, producing up to 5.4 ± 1.6 g schizophyllan/L and 6.0 ± 0.5 g schizophyllan/L for 1.0% (w/v) untreated and pretreated corn fiber, respectively. Glucose (from corn syrup) further enhanced yields, substituting for the maltose component of malt extract. Schizophyllan produced from corn fiber exhibited a high molecular weight of 3.2 x 107, with solution viscosity properties characteristic of schizophyllan. Utilization of corn fiber could reduce the cost of schizophyllan production and provide a value-added coproduct from corn processing biomass.