Q.The group of degradable biopolymers are :

PHAs and PHB are the standard example of biodegradable biopolymers (bioplastics) made by bacteria.

Several bacterial species (such as Ralstonia eutropha / Cupriavidus necator and certain recombinant E. coli strains engineered for the purpose) accumulate polyhydroxyalkanoates (PHAs) -- of which polyhydroxybutyrate (PHB) is the most common type -- as intracellular granules that store carbon and energy when nutrients such as nitrogen are limited but carbon is in excess. These polymers are thermoplastic, biodegradable, and can be moulded into packaging materials, surgical sutures and other bioplastic products that decompose naturally, unlike petroleum-based plastics, making PHAs/PHB a widely cited biotechnology example of a 'green' degradable biopolymer. In contrast, Cry1Ac is a Bacillus thuringiensis insecticidal protein gene used to make Bt cotton/B …