Utilization of kitchen waste for production of pullulan to develop biodegradable plastic

Pullulan has many useful characteristics but, its high cost limits its potential applications. In the present work, kitchen waste (KW), which otherwise has zero commercial value, was evaluated for the economical production of pullulan. Before fermentation, the KW was hydrolyzed into free sugars using an in-house produced cocktail of enzymes. During hydrolysis, 46 ± 3.5 g/l and 31 ± 2.2 g/l of total reducing sugars and glucose were released, respectively. Hydrolyzed kitchen waste was then used as substrate for fermentation by Aureobasidium pullulans MTCC 2013 yielding 20.46 ± 2.01 g/l pullulan. Further, effect of different nitrogen sources was evaluated and yeast extract (3%) was found to be the best, yielding (24.77 ± 1.06 g/l) exopolysaccharide (EPS). The pullulan produced from KW was characterized in terms of organoleptic properties, physical strength, Fourier-transform infrared spectroscopy (FTIR), and H nuclear magnetic resonance (H NMR) analysis. The results corroborated well with commercial pullulan. The biodegradable nature and water solubility of the film developed from pullulan was also confirmed. To the best of our knowledge, this is the first report on the validation of the biodegradability of in-house produced pullulan. Thus, kitchen waste appears to be a promising option for economical pullulan production. Additionally, the method may also prove to be helpful for managing the increasing load of municipal solid waste in an eco-friendly and scientific way.