Why is PLA polylactic acid costly?

The main reason for the high production cost of PLA polylactic acid is the process of manufacturing lactic acid with high optical purity (98~99%), and the key to maintaining a high level of fermentation efficiency in the traditional lactic acid bacteria fermentation process is the control of concentration, temperature, PH value, etc., as well as the cultivation of highly active fermentation bacteria. To this end, in order to improve the efficiency of fermentation, research is currently underway on the development of enzymes and strains, including biotechnology such as genetically modified organisms.