Enhancement of bioethanol production by Saccharomyces cerevisiae under high gravity fermentation using sequential optimization strategy

Mohammed, Heba E; Abo-Alkasem, Mohamed I.; Ammar, Ehab M.; Mazeed, Tarek E.; Abu Taleb, Amira M

doi:10.21608/ejchem.2021.78360.3904

Enhancement of bioethanol production by Saccharomyces cerevisiae under high gravity fermentation using sequential optimization strategy

Document Type : Original Article

Authors

¹ Distillation Factories, Egyptian Sugar and Integrated Company, El-Hawamdia Giza, Egypt

² Chemistry of natural and microbial products, Pharmaceutical research division. National Research Centre, Giza, Egypt

³ Genetic Engineering and Biotechnology Research Institute, University of Sadat City, El-Sadat City, Egypt Patel College of Global Sustainability, University of South Florida, 4202 E. Fowler Avenue, Tampa, FL 33620, USA

⁴ Chemistry of Natural and Microbial Products Dept., Pharmaceutical and Drug Industries Research Div., National Research Centre, Dokki, Giza, Egypt Department of Chemical and Bimolecular Engineering, Ohio State University, United State of America.

⁵ Botany and Microbiology Department, Faculty of Science. Cairo University, Egypt.

10.21608/ejchem.2021.78360.3904

Abstract

Using high gravity fermentation for bioethanol production by Saccharomyces cerevisiae is faced with many challenges such as increasing osmotic stress and viscosity. Unfortunately, increasing specific gravity was accompanied by a decrease in fermentation efficiency. A two-stage sequential optimization strategy was carried out to solve this problem. The first stage was carried out using the Plackett-Burman Design in which eight factors were investigated at three molasses specific gravities (1.130, 1.145, 1.160). Urea, wheat bran, soy flour, and inoculum size were significant model terms and had positive effect on bioethanol production. When a validation test was performed using the predicted conditions, about a more than two-fold increase in fermentation efficiency (FE) was achieved (83%) at specific gravity 1.130, compared to the basal condition. The second stage (Taguchi Design) was conducted using eight factors. Urea, wheat bran, temperature, and agitation speed showed a significant effect on fermentation efficiency. A validation test was carried out and up to 83.82 % fermentation efficiency was recorded, which was very close to that achieved under normal gravity. In addition to the high value of FE, this strategy is cost-effective and time-saving.

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