Valorisation of Waste Bread for the Production of Yeast Biomass by Yarrowia lipolytica Bioreactor Fermentation


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Carsanba E., Agirman B., Papanikolaou S., Fickers P., Erten H.

Fermentation, vol.9, no.7, pp.1-14, 2023 (SCI-Expanded)

  • Publication Type: Article / Article
  • Volume: 9 Issue: 7
  • Publication Date: 2023
  • Doi Number: 10.3390/fermentation9070687
  • Journal Name: Fermentation
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED)
  • Page Numbers: pp.1-14
  • Çukurova University Affiliated: Yes

Abstract

The increase in the wastage of bread, representing 12.5 million tons per year, causes ecological problems, such as the production of methane and CO2 , when that waste bread (WB) is improperly managed. To reduce this ecological footprint, a more sustainable system of WB management must be set up. Based on its chemical composition, WB has a high potential to be used as feedstock for microbial growth and conversion into value-added bio products. The microbial valorisation of WB is a novel biotechnological approach to upgrading a waste into a renewable feedstock for bio-based industry, thus favouring the circular economy concept. Based on this, the aim of this study was to test WB as a feedstock for biomass production by Yarrowia lipolytica, which can be considered as a promising supplement for animal and human dietary products. The enzymatic hydrolysis of WB was primarily optimized for large-scale production in a bioreactor. The biomass production of Y. lipolytica strain K57 on WB hydrolysate-based media in batch bioreactor culture was then investigated. As a result, a very high starch to glucose conversion yield of 97% was obtained throughout optimised hydrolysis. At the end of 47 h of batch culture, a biomass higher than 62 g/L, specific growth rate of 0.37 h−1 and biomass yield of 0.45 g/g were achieved from a WB hydrolysate. Therefore, this study demonstrates that WB hydrolysate has a promising potential to be used as a feedstock for biomass production by Y. lipolytica strain K57 for food and animal diet applications.