Optimization Of Fermentation Conditions Of Microbial Transglutaminase

Microbial transglutaminase (protein-glutamine- γ -glutamytransferase) is an enzyme capable of catalyzing acyl transfer reactions in vitro introducing covalent cross-links between proteins as well as peptides and various primary amines. These transglutaminase catalyse reaction can be used to modify the function of proteins.so it has potential application in food cosmetic, pharmacy and other industries. However , still much work has to be done before this interesting enzyme can be produced on an industrial scale commercially.To realize an economic and practial process,development of fermentation process with a high MTG activity .The major contents of research include: (1) Effects of the component of fermentation medium on shake-flask culture.(2)Effects of artificial zeolite on MTG production and mechanism for artificial zeolite to stimulate MTG activity. (3) Optimization of fermentation conditions and fermentation in 10 L fermentor are investigsted.Main results are followed:1. Effects of different organic nitrogen were investigsted on MTG production by Streptomyces in shaking flasks.The results showed that the hydrolysate of soybean flour in high pressure served as the optimum source.MTG activity could reach 3.86u/mL.The optimum condition of hydrolysis of soybean flour is as followed:suitable concentration of hydrochloric acid is 2 mol/L,hydrodysis time is 1hour. Studies have been made to different inorganic nitrogen and carbon sources on the effects of production of transglutaminase. The result showed that the activity of MTG was increased by adding up ammonium sulphate(0.3%) in to the liquid medium, And the effective carbon sources was glycerol. Bean oil and colza oil had no use to MTG production. The influencesof composition factor were investigated by L9(3~4) test .The importance factor was elucidated by hydrolysate of soybean flour, yeast extract and glycerol and the compnsition offermentation medium was optimized by the Response Sueface Anlysis(RSA). The most suitable composition of fermentation medium were as followed: hydrolysate of soybean flour 2.4%,yeast extract 0.5%, glycerol 2.4%, ammonium sulphate 0.3%.2. MTG activity was decreased when ammonium sulphate was adding during the mid-later phase of fermentation. And MTG activity was increased by adding 1% artificiak zeolite. Studies has made by the effects of artificial zeolite on MTG activity,metabolism of carbon source and ammonium,DCW, pH.So the reason artificial zeolite to stimulate MTG activity was conjecture realated to ammium.3. The proper culture conditions of shake-flask were that seed age was 32 h,inoculum size was 7%-10%,fermentation time was 48 h.The result of fermentation in 10 L fermentor was similar with shake-flask.But the fermentation time was short.