Polysaccharides production by yeast in whey ultrafiltrate

Abstract

Various forms of bioconversion of lactose from whey ultrafiltrate to absorbable carbon components have been studied with the purpose of utilizing whey ultrafiltrate as a substrate for synthesis of exopolysaccharides from the lactose-negative strain Rhodotorula acheniorum MC. In this connection, the influence of preliminary enzyme hydrolysis of lactose from whey ultrafiltrate on polysaccharides production has been studied. The biosynthetical ability of Rh. acheniorum MC grown together with Kluyveromyces marxianus var.lactis MC5 on whey ultrafiltrate has been tested as well as the symbiosis between the species Rh. acheniorum and Lactobacillus casei subsp. casei. It has been determined that the yeast strain-producer, when in association with the lactic acid strain Lactobacillus casei 91, shows higher activity in the production of polysaccharides (9.35 g/L) than when it is associated with K.marxiamts var.lactis MC5 (7.8 g/L). The biological system including the Rh.acheniorum MC + K.marxianus var.lactis MC5 association grown on whey ultrafiltrate (4.1% lactose) in air flow conditions 4.55 L min-1 synthesized a polysaccharide whose D-mannose concentration (71.6%) was the highest of all polysaccharides produced. © 1994 Taylor & Francis Group, LLC.