Fully biodegradable PLA stic bag

What is a fully biodegradable PLA stic bag?Fully biodegradable PLA stic bags: fully biodegradable PLA stics are mainly composed of natural polymers(Such as starch, cellulose, chitin)Or agricultural and sideline products are made by microbial fermentation or synthetic biodegradable polymers, such as thermo PLA stic starch PLA stics, aliphatic polyesters, polylactic