The Study On Pilot-scale Fermentation Of Tannase Using A Packed-bed Solid-state Incubator

Tannase,as an enzyme which can catalyze the hydrolysis of ester bonds in tannins,has broad application foreground.In this study,tea stalk,a low-cost substrate,were used for tannase production in a pilot-scale solid-state incubator by Aspergillus niger.The main results are listed as follows.Single factor experiments showed that the optimal tannase production was obtained when conducting fermentation at nature pH,25℃and moist level at 65%and humidity at 60%.In the flask fermentation,the tannase activity reached 32 U/gds,which was 1.4 fold of that of the initial condition.In the tray fermentation,the tannase activity reached 26.12 U/gds,which was 80.8%of that of flask fermentation.Based on analysis of the solid-state fermentation process process,the packed-up solid-state incubator was designed in aspects of general layout and the air circulation.In addition,corresponding spray device,temperature and humanity sensor,shift wheels and drainage exit was designed.The critical fluidization velocity was calculated at 0.0071 m/s,and the required quantity of air was 60~3m/h.When controlling the ventilation rate in a range of 10 to 20~3m/h,it had mild effects on the tannase production;a higher ventilation rate shows a better ability to heat removing.Tannase production was increased by 0.95 times and the time that enzyme reached maximum activity was shortened to 48 h after the disinfection of the incubator using a solution of 500 mg/L of NaClO compared to no disinfection.Based on the investigation of decolonization and concentration technology,the process consisting of decolonization using activated carbon,filtration sterilization,concentration using membrane technology and frozen dry was figured out and applied to produce tannase from 50 L tannase extract to 224 gram of tannase powder with a enzymatic activity of 36.3 U/g and enzymatic recovery of 52.7%.On this base,a scaled-up process was set up.This work optimized the conditions of tannase fermentation,designed pilot solid-state incubator to scale up fermentation and finished the process design of tannase production.Those provided an important technology reference for tannase production.