실관반응기에 주반응효소(leucine dehydrogenase), 재상반응효소(formate dehydrogenase), 그리고 고분자 조효소 유도체(dextran-NAD⁺)를 고정화시켜 연속적으로 루이신을 생산하였다. 실관반응기의 루이신 생산은 34시간 유지되었고 최고 전화율이 83%, 평균전화율이 76%였다. Space time yield는 78.2g/L/d(또는 596mmol/L/d)의 높은 값을 얻었는데 이러한 높은 space time yield 값은 발효공정으로는 얻기 힘든 효소반응기의 장점이라 하겠다. 효소반응시 조효소 유도체의 retention coefficient는 평균적으로 87%, 최고 91%이었고, resi-dence time은 평균적으로 1시간 정도를 유지하였다. 조효소유도체의 turn over number는 8500을 넘어섰다. 결과적으로 조효소재생방법을 사용하지 않은 경우의 루이신 kg생산당 NAD⁺비용을 재생방법에 의하여 약 10,000배로 줄여, 산화환원효소의 산업적 응용의 가장 큰 문제점이었던 조효소 비용문제를 해결하였다.

L-leucine was produced from α-ketoisocaproate in a hollow fiber enzyme reactor, where leucine degydrogenase(L-leucine:NADH oxidoreductase, EC1.4.1.9), formate dehydrogenase(formate:NAD⁺ oxido-reductase, EC1.2.1.2), and NAD⁺ covalently bound to water-soluble dextran(dextran-NAD⁺) were used as the catalytic enzyme, coenzyme regeneration enzyme, and enlarged coenzyme, respectively. The continuous-production of L-leucine in a hollow fiber enzyme reactor for 34hrs resulted in a space-time yield of 78.2g/L/d(or 596mmol/L/d) with a mean substrate conversion of 76%. After 34hrs, the reaction did not continue due to loss of enzyme activity. The turnover number of cofactor-retio of moles of product to moles of NAD(H)-exceeded 8,500. The cofactor regeneration scheme for NADH had been successful to the extent that cofactor cost was no longer dominant in the L-leucine production.

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