Medium Evaluation and Plastic Composite Support Ingredient Selection for Biofilm Formation and Succinic Acid Production by Actinobacillus succinogenes

Abstract

Succinic acid production medium for Actinobacillus succinogenes was simplified. Vitamins and fatty acids were removed from the medium and industrial quality yeast extract was substituted to yield revised succinic acid medium. Customized plastic composite support (PCS) blends were screened for biofilm and succinic acid production. Twenty different PCS blends with and without mineral salt additions were evaluated in twenty simulated repeated-batch fermentations using MgCO₃ for pH control and CO₂ supply. Succinic acid concentrations, percentage yield succinic acid, and biofilm formation for each PCS blend were determined. No correlation was observed for biofilm formation and succinic acid production. The selected customized PCS blend for A. succinogenes succinic acid production consisted of 50% (wt/wt) polypropylene, 35% (wt/wt) dried ground soybean hulls, 5% (wt/wt) dried bovine albumin, 2.5% (wt/wt) soybean flour, 2.5% (wt/wt) yeast extract, 2.5% (wt/wt) dried red blood cells, and 2.5% (wt/wt) peptone, which demonstrated 70% yields for succinic acid compared to 64% yield for suspended cell fermentation.

Acknowledgments

This research was supported by the Iowa Corn Promotion Board, the Center for Crops Utilization Research of Iowa State University, and the Iowa Agriculture and Home Economics Experiment Station. We also thank Dr. John Strohl and Jelena Jeremic for their technical support and use of equipment in the Iowa State University Fermentation Facility and Donghui Cheng and the Iowa State University Cell and Hybridoma Facility for flow cytometry sample processing. Journal paper No. J-3764 of the Iowa Agriculture and Home Economics Experiment Station, Ames, Iowa, Project No. 3764, and supported by Hatch Act and State of Iowa funds.