Statistical optimization of chitin extraction from mushroom wastes by lactic acid fermentation in a stirred tank bioreactor

Abstract

Chitin can be obtained using chemical degradation methods using crab and shrimp shell wastes. The process of extraction is wasteful and provides limited supply due to the seasonal availability. In the present study, mushroom wastes were subjected to fermentation-assisted extraction of value-added products such as chitin. The lactic acid fermentation process was optimized using statistical tools such as Plackett-Burman Design and Response Surface methodology and the optimal values of soli to liquid ratio was 60 g/l, inoculum size was 10% v/v and temperature was 30 °C. Batch fermentation of mushroom wastes was also performed using the optimized conditions in shake flasks and 7-L stirred tank bioreactor (STR). The experimental data obtained from the kinetic study was further utilized to determine the values of growth kinetic parameters. It was observed that at the end of 24 h the final Lactobacillus paracasei dry cell weight obtained in the stirred tank bioreactor was 0.43 g/l. Crude chitin harvested from the bioreactor was 0.15 g/g of mushroom wastes on dry cell weight basis and the residual mineral content was found to be 3.8 %. The growth kinetic data values determined from STR study will be utilized for further improvement of large-scale production of chitin using mushroom wastes.