Hydrolysis of Lactose in Milk by Microencapsulated ${\beta}-Galactosidase$

Microencapsulated ${\beta}-Galactosidase$에 의한 우유 유당의 가수 분해

  • Baik, Ok-Ryun (Department of Biological Science and Engineering The Korea Advanced Institute of Science) ;
  • Uy, Ro-Sa (Department of Biological Science and Engineering The Korea Advanced Institute of Science) ;
  • Byun, Si-Myung (Department of Biological Science and Engineering The Korea Advanced Institute of Science)
  • 백옥련 (한국 과학원, 생물 공학과) ;
  • 로사위 (한국 과학원, 생물 공학과) ;
  • 변시명 (한국 과학원, 생물 공학과)
  • Published : 1980.03.30

Abstract

The nylon (poly 6, 10) microcapsules containing ${\beta}-galactosidase$ were obtained by the interfacial polymerization of 1, 6-diaminohexane and sebacoyl chloride with ${\beta}-galactosidase$ from Escherichia coli. They were generally spherical and had a mean diameter of $80{\mu}$ with 45 % of the activity recovery. In particular, there was no transport hamper of lactose through the membrane of microcapsules. The characteristics of the microencapsulated enzyme were similar to those of soluble enzyme optimal pHs, $7.0{\sim}7.2$ for the soluble and $7.3{\sim}7.5$ for the microencapsulated ; optimal temperatures, $50^{\circ}C$ for both ; apparent $K_m,\;3.33{\times}10^{-4}(on ONPG),$ $2.86{\times}10^{-3}$ M(on lactose) for the soluble and $5.28{\times}10^{-4}$ (on ONPG), $4.25{\times}10^{-3}$ M (on lactose) for the microencapsulated ; activation energies, 8.94 for the soluble and 9.78 Kcal/mole for the microencapsulated enzyme. Using this microencapsulated ${\beta}-galactosidase$, hydrolyses of lactose and milk lactose were carried out and 80 % of 5 % lactose solution and 70 % of lactose in skim milk were hydrolyzed in 40 hr at $27^{\circ}C$. The reusability and operational stability showed that the remaining activity was 50 % of the original activity after 5 runs and 120 hr of total operating time at $27^{\circ}C$.

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