Isolation and characterisation of starch/polyvinyl alcohol degrading fungi from aerobic compost environment

• Starch/PVA crosslinked films have a great potential to be used as packaging films.
• Two fungi were isolated from the compost for degradation of starch/PVA films in laboratory.
• The fungi exhibited enhanced biodegradation rate than that observed in the compost.

Two fungi, responsible for the degradation of starch/polyvinyl alcohol (PVA) biocomposite films were isolated from aerobic compost environment by extensive screening. ITS (Internal Transcribed Spacer) sequencing of the two fungi samples showed 99% identity at 99% coverage with the sequence from Penicillium daleae, and 100% identity at 100% coverage with the sequence from Aspergillus flavus. An extensive weight loss study was performed using these two fungi on starch/PVA films separately. In comparison to the weight loss observed in the compost (nearly 60%), starch/PVA films exhibited a higher weight loss (nearly 71%) by these two fungi after 30 days of degradation. The borax crosslinked films exhibited 85% degradation by A. flavus. After 15 days of degradation by fungus closely related to P. daleae, the borax crosslinked films disappeared completely. This study showed that the A. flavus and fungus with close affinity to P. daleae can degrade such biocomposite films more efficiently in comparison to biodegradation in compost.

Aspergillus flavus and Penicillium daleae were isolated from a complex aerobic compost environment for degradation of starch/PVA films. Biodegradation studies were performed by these two fungi in petri dishes by using a minimal agar media. Weight loss study indicated an increased rate of degradation in lab in comparison to that observed in compost. Borax crosslinked films totally disappeared after 15 days of degradation. However micro crystalline cellulose (MCC) did not have any significant effect on degradation.Figure optionsDownload as PowerPoint slide