Fractionation of spent brewer's yeast for high value-added biomolecules production

Author(s)

Edson Marcelino Alves

• Document type: Doctoral Thesis
• Press: Rio Claro. 2020-11-02.
• Institution: Universidade Estadual Paulista (Unesp). Instituto de Pesquisa em Bioenergia. Rio Claro
• Defense date: 2020-06-26
• Advisor: Pedro de Oliva Neto

Abstract

Currently, the yeast biomass is an underutilized waste product of brewing industry. Moreover, the use of this biomass can be an economical source for the extraction of several compounds such as yeast extract, proteins, β-fructofuranosidase, RNA and 5'-ribonucleotides, which are by-products with wide applications in pharmaceutical and food industry. Faced with these issues, the objective of this work was to study and design an integrated bioprocess methodology using spent brewer’s yeast biomass as feedstock for obtaining several high added value biomolecules through fractionation and downstream techniques. For this, the biotechnological potentials of yeast utilization are reviewed in the Chapter 1. The Chapter 2 presents the results of the initial stages of preparation and characterization of yeast from the brewing industry as well as the evaluation of autolysis parameters in order to maximize RNA extraction for subsequent 5'-ribonucleotides production. The Chapter 3 describes the use of acid shock at the beginning of autolysis in order to accelerate the autolytic process and the extraction of proteins. The results of enzymatic hydrolysis of RNA to produce 5'-ribonucleotides using 5'-phosphodiesterase from residual malted barley roots is presented in the Chapter 4. The recovery of extracellular β-fructofuranosidase enzyme as the first by-product before autolysis and studies on its immobilization in sodium alginate and activated charcoal beads were described in the Chapter 5. Finally, an economic analysis as well as a bioprocess plant design for yeast processing is proposed in the Chapter 6 in order to determine the profitability and financial viability of the methodology developed in this work. The proposed approach indicates an excellent strategy, since a better use of spent yeast from fermentation processes in the proposed biorefinery plant can open up a range of applications and add value to this product, making the industrial sectors more profitable. (AU)

• FAPESP's process: 16/08886-6 - Integrated fractionation processes of Saccharomyces cerevisiae from the brewing industry for the production of high value-added biomolecules
• Grantee: Edson Marcelino Alves
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)