Evelopments in biodegradable bioplastics

Please include
-todays problem with traditional plastics briefly and how bioplastics are an answer
-types of biodegradable bioplastics(compare processing methods,applications,marketability,production costs-compare to traditional plastics and between each other,disposal,market share,trends,degradation mechanisms)
-Potential positive and negative(contradictory)impacts
-Narrow it down to PLA as my aim is To determine the sustainability,opportunities and challenges facing PLA in the bioplastics industry”(with special emphasis on resources availability if we replace 50% petroleum plastics with polylactate.Also, is PLA manufacture cost effective and mostly degradability and disposal of PLA after use)
-I have the marking scheme and a PLA review paper my supervisor recommended that I will attach