Biodegradation of Seaweed-based Bioplastics Using Deep-sea Marine Bacterial Consortia

Thin plastic films used for packing food materials are unsafe for consumers and are not readily degradable. Single-use plastic films accumulate in the environment and cause adverse effects in the food chain. In this study, Kappaphycus alvarezii, which has the value-added polymer carrageenan, was used for developing a bioplastic film along with the plasticizer polyethylene glycol (PEG 3000). Different concentrations of seaweed were used (3%, 4% and 5% dry weight), of which 4% had a higher tensile strength than the other concentrations. The physical and mechanical properties of the developed plastic films, such as thickness, tensile strength (TS), water vapor transmission rate (WVTR), oxygen transmission rate (OTR) and color, were tested for packaging applications in the food industry. A higher concentration of seaweed increased the WVTR, and a lower concentration increased the OTR. In addition, the biodegradation of the developed bioplastic was tested using isolated deep-sea microbial consortia to meet environmental standards. A deep-sea marine microbial consortium (Bacillus paralicheniformis G1, Bacillus subtilis G2, Bacillus subtilis Z1, and Enterobacter cloacae subsp. dissolvens Z2) degrades seaweed (Kappaphycus alvarezii)-derived bioplastic under buried soil conditions. The maximum degradation (88%) in the 5% (w/v) bioplastic film was observed within 10 days of incubation.

Graphical Abstract