On the other hand, the big problem of fossil plastic is it accumulation[5] . For example, if we suppose a constantly production of the same amount of PLA and PET (a fossil plastic), after 5 years, it would expect find a higher amount of PET than PLA due to a percentage of PLA should be degraded in the first two years[6] . But if PLA had a short degradation time, we guess people maybe would replace it more frequently, so higher amount of PLA product could be thrown away and maybe accumulation rate could be higher than degradation rate. We think this kind of trade off should need further analysis to evaluate the real impact of uses of PLA.
According to functionality of PLA, we recommend it to products which will have a short life-time (<2 years), for example plastic glasses or bags. Contrarily, to products that need a long life-time, for examples piping, big structures, it would be appropriate to remain using fossils plastic. On the particular case of medical use, we think PLA should be used like suture, because sutures need to be degraded in a short time [ref suture].