The aim of this study is the consolidated bioprocessing of lactose into lactic acid and ethanol using nonengineered Cell Factories (CFs). Therefore, two different types of composite biocatalysts (CF1-CF2) based on Saccharomyces cerevisiae with immobilized microorganism or enzyme on starch gel (SG) were prepared for 5% w/v lactose fermentation. In CF1, S. cerevisiae was covered with SG containing Lactobacillus casei, Lactobacillus bulgaricus, Kluyveromyces marxianus CF1a-c. S. cerevisiae/SG-β-galactosidase (CF1d) was also used for simultaneous saccharification and fermentation (SSF) of lactose. In CF2, S. cerevisiae immobilized on tubular cellulose (TC) was covered with SG containing the aforementioned microorganisms (CF2a-c). The wet CF1d resulted in 96% of the theoretical ethanol yield while the wet CF1b and freeze-dried CF2b resulted in 89% of the theoretical lactic acid yield. The repeated batches using the CF2a-c exhibited better results than using CF1a-c. Subsequently, the freeze-dried CF2 as preservative and more manageable were verified for future exploitation of whey.
Bibliographical noteFunding Information:
Authors acknowledge support of this work by the project “Research Infrastructure on Food Bioprocessing Development and Innovation Exploitation – Food Innovation RI” (MIS 5027222), which is implemented under the Action “Reinforcement of the Research and Innovation Infrastructure”, funded by the Operational Programme “Competitiveness, Entrepreneurship and Innovation” (NSRF 2014-2020) and co-financed by Greece and the European Union (European Regional Development Fund).
© 2021 Elsevier Ltd
- Consolidated bioprocessing of lactose
- Non engineered cell factory, S. cerevisiae
- Whey exploitation