Microbial Transformation Of β-aminopropionitrile To β-alanine

A recently isolated microorganism was used for transformation ofβ-aminopropionitrile toβ-alanine. The conditions of transformation with resting and immobilized cells were optimated. Ion exchange method was successfully employed in the separation ofβ-alanine from the reaction mixtures.The better results ofβ-alanine production were obtained by resting cells under the optimal biotransformation conditions of temperature 32℃and pH Value 7.0 in phosphate buffer solution. Cell enzyme activity of transfromation fromβ-aminopropionitrile toβ-alanine could be significantly inhibited by Zn²⁺ and Cu²⁺ , whereas it can be improved by Ca²⁺. Substrate inhibition could occur whenβ-aminopropionitrile concentration reach 0.9% or above. At lower substrate concentrations, reaction kinetics was investigated. And its V_m and K_m were 2.47×10^-4 mol/Lmin and 2.94×10^-3 mol/L respectively.The optimal biotransformation conditions by cells immobilized with sodium alginate in saline (pH 7.0) were as follows: pH 7.5, temperature 35℃. The V_m and K_m of the immobilized cells were 9.69×10^-5 mol/Lmin and 3.94×10³ mol/L respectively. Compared with flee cells, the enzyme activity of immobilized cells was more stable. After 8 batches, 80.2% enzyme activity of the immobilized cells was remained.Ion exchange technology was chosen for the separation ofβ-alanine from reaction mixture. The results demonstrated thatβ-alanine can be effectively separated with WA-2 amino special resin and D201-FC resin.