For some bio-based plastics and the positive controls (cellulose
paper), the initial rate of mineralization was rapid (Fig. 1). Most of
the mineralization took place during the first 300 days of incubation
(Fig. 1). The most rapid initial rate of conversion was observed
for co-polyester þ corn-based plastic with almost 34.6 2.4%
mineralized during the first 55 days of the experiment. The extent
of PHA biodegradation was initially lower, but its extent surpassed
that of co-polyester þ corn-based plastic after approximately 280
days reaching a value of 48.5 4.6%. For the wheat starch-derived
plastic and plastarch conversion rates were 14.2 0.8 and
24.6 1.4% after 110 and 280 days of experiment, respectively.