Electrically-assisted extraction of bio-products using high pressure disruption of yeast cells (Saccharomyces cerevisiae) Original Research Article

The efficiency of combined electrically-assisted high pressure homogenization techniques for disruption of wine yeast cells (Saccharomyces cerevisiae bayanus, strain DV10) in an aqueous suspension (1% w/w) was studied. The pulsed electric field (PEF) and high voltage electric discharge (HVED) were applied at electric field strengths of 10 kV/cm and 40 kV/cm, respectively. The high-pressure homogenization (HPH) technique was applied within pressure range 30–200 MPa at different number of passes (1–20). Releasing of intracellular ionic content was characterized by conductivity disintegration index Z (0–1), releasing of high molecular weight content was analyzed using spectroscopy and electrophoresis methods. It was shown that releasing efficiency of ionic components, enzymes, proteins and other bio-products dramatically depended on the applied method of disruption. Extraction efficiency was rather high for ionic components and small for high molecular weight components in PEF or HVED pre-treated suspensions. However, application of the combined HVED-HPH technique resulted in material loss of integrity by yeast cell walls. Even small disintegration (Zi = 0.15 ± 0.05) initially induced by HVED pre-treatment resulted in noticeable acceleration of HPH disruption kinetics. The proposed combined HVED-HPH technique may have a good potential in future biotechnological and food applications.