The main aim of this research was to utilise whey as a fermentation substrate for the production of microbial biopolymers.Of the three commercial biopolymer producers tested for biopolymer production in whey, only Pseudodomonas elodea produced significant apparent viscosities of up to 470cP at 2 s-1 on enriched whey broths. In these broths lactose utilisation was poor (14% w/v). A strain of P. elodea that had improved lactose utilising capacity was selected after six serial transfers on whey and lactose rich broths. After screening more than 60 bacterial isolates, a strain of Klebsiella oxytoca that initially produced a broth apparent viscosity of 36 cP at 12 s-1 in whey was isolated from raw milk. Biopolymer production was optimised in the K. oxytoca isolate.Concentrations of over 16 g/1 and broth apparent viscosities greater than 20,000 cP at 0.6 s-1 were obtained after optimisation. The biopolymer produced by the K. oxytoca isolate was shown to contain rhamnose, glucose and cellobiose, a composition not comparable to any reported polysaccharide. Polymer application studies indicated that it had potential to be used as a thickener, stabiliser, and binder. / Doctor of Philosophy (PhD)