Since PHB was discovered in B. megaterium in 1925, its existence has been confirmed in more than 60 genera of bacteria, such as Alcaligenes (Alcaligenes), Azotobacter (Azotobacter) and Pseudomonas (pseudomonas). Spp.), etc. In some G+ and G- bacteria, as well as some photosynthetic anaerobes and chemoautotrophic Rastonia eutropha (Rastonia eutropha), a variety of compounds similar to PHB have been found, collectively called polyhydroxy chains Alkanoic acid (or polyhydroxyalkanoate, PHA), the difference between them and PHB is only on the methyl group, if the methyl group is replaced by R (abbreviation for radical, refers to a certain group), then Become PHA. As PHB and PHA are biosynthetic polymers, which are non-toxic, plastic and easily degradable, they are vigorously developing high-quality raw materials for the manufacture of medical plastic boxes, fast food boxes, etc., and are trying to overcome the current serious harm "White pollution" (refers to environmental pollution caus…