Abstract

Economic production of polyethylene modifying lipase enzyme under solid state fermentation using banana peels and sand

Author(s): Magda A.El-Bendary, Maysa E.Moharam, Doaa A.R.Mahmoud

Agro –industrial by-product residues were used as substrates in the presence of sand as a carriermaterial for production of polyethylene surface modifying lipase enzyme under solid-state fermentation from Bacillus isolateW5. Banana peels supported the highest enzyme production at 4.5- 6%(732U/g of fermented culture).Maximumlipase productionwas achieved at 10%initialmoisture content and 30Cincubation temperature. Enrichment of the medium with ammonium acetate as carbon sources increased the enzyme production about 31%. On the other hand, the nitrogen source, peptone enhanced the enzyme production by 28%. Optimuminitial pH and incubation period were pH 7 and 5 days, respectively. Calcium chloride and potassium chloride at 1% enhanced enzyme productivity by 12% and 9%respectively. Supplementation themediumwith surfactant has no effect on enzyme productivity. Pilot scale production of lipase enzyme under the optimumSSF conditions was tested in aluminumtrays. The lipase activity was 1397 U/g fermented culture. This result was comparable with that obtained frombench scale production (in flasks). The cost of one kilogram of this fermented culture containing 1397000 U of lipase was estimated as US $ 2.4. The enzyme showed the highest activity at 70C and pH 8.5. It was stable up to 50C for 15 min and pH range 5-9 for one hour. The obtained results were discussed in the light of possible utilization of banana peels and sand for the production of this important industrial enzyme under solid state fermentation.