Production of ${\delta}-Aminolevulinic$ Acid in Soybean Curd Wastewater by Rhodobacter capsulatus KK-10

두부공업폐수에서 Rhodobacter capsulatus KK-10을 이용한 ${\delta}-Aminolevulinic$ Acid의 생산

The removal efficiency of COD and the production of ${\delta}-aminolevulinic$ acid (ALA) were concurrently investigated for both purifying the soybean curd wastewater of high BOD and utilizing the wastewater as a renewable substrate of ALA production using Rhodobacter capsulatus KK-10. Its wastewater was a favorable media for the growth of photosynthetic bacteria in terms of its environmental characteristics having COD/BOD rate of 0.98, ratio of BOD : N : P=100 : 6 : 4, BOD/N ratio of 17.2, lactic acid of 1,080 ppm. Its COD value wastewater was decreased to 94% and dry cell weight was approached to about 1.2 g/l after cultivation of the photosynthetic bacteria for 4 days. By the addition of 15 mM levulinic acid (LA) into the wastewater at the middle log phase of cell growth, the amount of ALA secreted was 55 mg/l. The ALA production was considerably increased to 114 mg/l under the cultural condition of 15 mM supplementations of glycine and succinate with LA at the same period. Furthermore the maximum ALA production of 120 mg/l and COD removal efficiency of 92% were accomplished in the soybean curd wastewater enriched with one addition of 15 mM LA and three serial additions 15 mM ALA precursors.

광합성세균을 이용한 고농도 유기폐수인 두부공업폐수의 정화처리와 동시에 두부공업폐수를 생물제초제인 ${\delta}-aminolevulinic$ acid (ALA) 생산용 대체기질로 이용할 목적으로 Rhodobacter capsulatus KK-10을 사용하여 COD 제거율과 ALA 생산능을 검토하였다. 사용된 두부공업폐수의 성상은 pH 4.2, COD/BOD와 BOD/N의 비율은 0.98 및 17.2, BOD : N : P의 함유비율은 10 : 6 : 4, 젖산 함유량 1,080 ppm 등으로 광합성세균의 생육에 적당한 조건이었다. 두부공업폐수에서 본 균주를 4일 동안 배양한 결과 약 94% COD 값의 감소와 1.2 g/l 균체생육을 보였으며 대수기 중기에서 ALA 탈수효소 저해제인 levulinic acid(LA)를 15 mM 첨가한 결과 55 mg/l의 ALA 생산량을 나타내었다. ALA의 전구물질인 succinate 및 glycine과 LA를 각각 15 mM의 농도로 동시 첨가시 최대 114 mg/l의 생산량을 보였다. 상기의 물질들을 각각 15 mM 농도로 연속 첨가한 후 ALA 생성량을 검토한 결과 LA 1회와 glycine과 succinate를 3회에 걸쳐 첨가하였을 때 120 mg/l로 가장 효과적이었으며 COD 제거율은 92%를 나타내었다.