In this study we investigated the effect of starch amendment on alpha-glucosidase activity in an organic waste environment, treated under both mesophilic and thermophilic conditions. The relative effects of temperature on alpha-glucosidase activity with regard to in situ and assay conditions were investigated under a reciprocal design. The decline in dry matter under the different thermal regimes was consistent with the temperature independent degradation of starch. The results of extra-cellular enzyme analysis showed a significant relationship between starch addition and alpha-glucosidase activity, with evidence of thermal adaptation to the in situ temperature. A weaker, but significant, effect of starch addition on beta-glucosidase activity was observed, with no evidence for thermal adaptation. Thus, our data is consistent with a substrate adaptive response to temperature, albeit under potentially a high selective pressure. (C) 2012 Elsevier Ltd. All rights reserved.