By-product formation by a novel glycerol-producing yeast, Candida glycerinogenes, with different O₂ supplies

Abstract

Candida glycerinogenes is an aerobe which does not depend on sulphite for production of glycerol. With a sufficient O₂ supply, up to 130 g glycerol l⁻¹ was produced with 2.6 g acetic acid l⁻¹ as by-product. However, with an insufficient O₂ supply – with higher volumes of medium or at higher corn steep liquid concentrations – the glycerol concentration was lower because the by-products, ethanol, pyruvate and lactic acid, were produced in greater amounts, up to 45 g l⁻¹, 4.3 g l⁻¹, 1.6 g l⁻¹, respectively, whereas, less acetic acid (0.6 g l⁻¹) was produced. In addition, ethanol decreased to 0.4 g l⁻¹ and the glycerol yield improved from 34 to 50% (w/w) by adding 50 g sulphite l⁻¹, nevertheless, acetic acid increased to 7.8 g l⁻¹.