혼합미생물배양체를 이용한 폐활성슬러지 가용화 산물로부터 polyhydroxyalkanoate 생합성 (Biosynthesis of polyhydroxyalkanoate by mixed microbial cultures from hydrolysate of waste activated sludge)

서지정보

· 발행기관 : 한국미생물학회
· 수록지 정보 : 미생물학회지 / 53권 / 3호 / 200 ~ 207페이지
· 저자명 : 박태준, 유영재, 정동훈, 이선희, 이영하

초록

SA-TSA 복합구를 이용해 폐활성슬러지로부터 VFAs를 생 산하고, 이를 발효 기질로 이용해 PHA를 생산하기 위한 실험 을 수행하였다. 30%의 SA-TSA 복합구를 처리하였을 때 폐활 성슬러지의 가용화 효율이 가장 효과적으로 일어나서 약 3,900 mg/L의 SCOD값을 얻었으며, acetic acid, propionic acid, isobutyric acid 및 butyric acid를 주성분으로 하는 2,961 mg/L 농 도의 VFAs를 얻었다. VFAs를 외부탄소원으로 이용하는 SBR 공정을 통해 PHA를 생합성하는 미생물을 농화배양하는 실험 을 수행하고 PCR-DGGE로 분석한 결과, 우점 미생물로 Vibrio spp.와 Corynebacterium glutamicum이 확인되었다. 폐활성슬 러지로부터 얻은 VFAs를 탄소원으로 사용하여 농화된 혼합 미생물배양체를 회분배양한 결과, 건체량의 25.9%에 달하는 PHB를 얻었다. 본 연구결과는 SA-TSA 복합구를 이용하여 폐 활성슬러지로부터 VFAs를 얻음으로써 폐슬러지 감량화 효 과를 얻고, 또 혼합미생물배양체를 이용하여 VFAs를 바이오 폴리머로 전환함으로써 경제성을 확보할 수 있는 새로운 생물 공정의 가능성을 보여준다.

영어초록

A new approach to the solubilization of waste activated sludge(WAS) using alginate-quaternary ammonium complex beads wasinvestigated under controlled mild alkaline conditions. The complexbeads were prepared by the reaction of sodium alginate (SA)with 3-(trimethoxysilyl)propyl-octadecyldimethylammoniumchloride (TSA) in acid solution, followed by crosslinking withCaCl2. Treatment of WAS with SA-TSA complex beads waseffective for enhancing the efficacy of WAS solubilization.
The highest value of soluble chemical oxygen demand (SCOD)concentration (3,900 mg/L) was achieved after 10 days oftreatment with 30% (v/v) SA-TSA complex beads. The WASsolubilization efficacy of the complex beads was also evaluatedby estimating the concentrations of volatile fatty acids (VFAs).
The maximum value of VFAs was 2,961 mg/L, and the overallproportions of VFAs were more than 75% of SCOD. The maincomponents of VFAs were acetic, propionic, iso-butyric, andbutyric acids. These results suggest that SA-TSA complexbeads might be useful for enhancing the solubilization of WAS.
The potential use of VFAs as the external carbon substrate forthe production of polyhydroxyalkanoate (PHA) by a mixedmicrobial culture (MMC) was also examined. The enrichmentof PHA-accumulating MMC could be achieved by periodicfeeding of VFAs generated from WAS in a sequencing batchreactor. The composition of PHA synthesized from VFAs mainlyconsisted of 3-hydroxybutyrate. The maximum PHA contentaccounted for 25.9% of dry cell weight. PHA production bythis process is considered to be promising since it has a doublybeneficial effect on the environment by reducing the amount ofWAS and concomitantly producing an eco-friendly biopolymer.

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