Abstract
We previously reported that cell flocculation is induced under conditions of light plus low temperature to avoid photoinhibition in Thermosynechococcus vulcanus RKN and that the flocculation is released by treatment with cellulase. However, the substance responsible for the aggregation could not be evaluated properly, since it was not completely digested even after excess treatment of cells with cellulase.
Here, we established the protocol for quantitation of cellulose by combination of the cellulase digestion with pretreatment of cells with sonication in ethanol. With this method, we evaluated cellulose accumulation in the process of the low temperature-induced cell flocculation. While cells began to aggregate at 24 h and mostly completed in 72 h, the cellulose accumulation preceded the aggregation and was maintained up to 72 h. Under the regular growth conditions, very little accumulation of cellulose was detected. These results suggest that cell flocculation is caused by cellulose accumulation.
