@Georgesplane- Polylactic acid is a great alternative to food manufacturers that are looking buy plastic resin food containers, but some of the benefits have been a little misleading.
Indeed, PLA is more environmentally friendly. According to the Smithsonian, it takes 65% less energy to produce, and emits 68% less emissions, than PET plastic. PLA also only costs about a dollar a pound to make.
The problem is in the biodegradable claims of PLA. PLA is only biodegradable in industrial composting operations, and most of those operations do not accept consumer waste. PLA also creates lactic acid when it breaks down, so compost cannot have concentrations of PLA that are too high, or the compost will be too acidic. For PLA to become a wonder plastic, the industry must develop the waste management channels for PLA.