Symbiotic utilization of polyvinyl alcohol by mixed cultures.

Polyvinyl alcohol (PVA)-utilizing cultures were obtained from various sources. They were mixed cultures even after cyclical transfer to liquid and plate media with PVA as a sole source of carbon. Component bacteria were isolated from the several mixed cultures, and it was shown that PVA was utilized symbiotically by two bacterial members which could not utilize PVA in each respective pure culture. From a mixed culture, strains VM15, VM15A (Pseudomonas putida) and VM15C (Pseudomonas sp.) were isolated as members essential for PVA utilization. VM15C was the predominant strain in the mixed-culture population and produced PVA-degrading enzyme. The culture supernatant of VM15A enabled VM15C to grow on PVA. VM15A was presumed to supply VM15C with a unique growth stimulant which was distinct from usual growth factors.