Polycaprolactone degradation by mixed and pure cultures of bacteria and a yeast

The degradability of three high molecular weight polycaprolactones (M̄ w = 35,000, 18,600, and 7,130) and one low molecular weight polycaprolactone diol(M̄ w = 2060) by mixed and pure cultures of microorganisms was assayed. A yeast, Cryptococcus laurentii , a gram‐negative rod, Acinetobacter calcoaceticus var. lwoffi , and a gram‐positive coryneform rod were used in the pure culture assays. The analysis of degradation by gel permation chromatography (GPC) allowed for quantitation independent of the growth of the organisms or the addition of supplementary growth factors. GPC analysis showed that the degradation effected by pure cultures was often enhanced when alternate carbon sources were present. This was not the case for mixed cultures. Mixed cultures. Mixed cultures completely metabolized polymer breakdown products while in some cases pure cultures did not.