Production of ω-hydroxynonanoic acid from soybean oil via Baeyer-Villiger monooxygenase-based biotransformation

Abstract

Plant oils and fatty acids are one of the most abundant renewable biomass in nature. Soybean oil, which is produced over multi-million tons per year, is mostly used as cooking oils, while only a small portion is used in the chemical industry. Thereby, biotransformation of soybean oil to value-added chemicals (e.g., 9-hydroxynonanoic acid) was investigated in this study. The biotransformation pathways were established first on a basis of previous studies, which consisted of hydrolysis of soybean oil by a lipase to glycerol and fatty acids including oleic acid and linoleic acid. The unsaturated fatty acids are further converted into ester acids via 10-hydroxy- and 10-keto-fatty acids by a serial reaction of the hydratase and recombinant Escherichia coli-based biocatalyst harboring an alcohol dehydrogenase (ADH) and a Baeyer-Villiger monooxygenase (BVMO). The ester acids are hydrolyzed finally to 9-hydroxynonanoic acid and C9 carboxylic acids. The lipase and the fatty acid double bond hydratase, which are very active to the reaction substrate and intermediates, were screened and their reaction properties were examined. By combining the lipase and the fatty acid double bond hydratase with the recombinant E. coli expressing the ADH of Micrococcus luteus and the BVMO of Pseudomonas putida KT2440, soybean oil was transformed into 9-hydroxynonanoic acid, n-nonanoic acid, and n-non-3-enoic acid. The biotransformation allowed to produce 10.8 mM of ω-hydroxynonanoic acid within 8 h from 5 g/L of soybean oil. Moreover, 5.5 mM of azelaic acid was produced from 5 g/L of soybean oil by combining the biocatalysts with recombinant E. coli expressing the alkJ of P. putida. These results indicated that the high value carboxylic acids ω-hydroxynonanoic acid and azelaic acid can be produced from a renewable raw material via biotransformation.;식물성 오일과 지방산은 자연계에서 가장 풍부한 재생 가능한 생물 자원이다. 연간 수백만 톤이 생산 되는 콩기름은 조리용 기름으로 가장 널리 사용이 되며 화학 산업에서는 적은 부분에서 사용이 된다. 따라서 본 연구에서는 콩기름에서부터 고부가가치 산물 (e.g., 9-hydroxynonanoic acid)로 생물 전환이 연구되었다. 생물 전환 경로는 선행연구 결과에 기반으로 하여 만들어졌으며, lipase에 의해 콩기름이 글리세롤과 oleic acid와 linoleic acid를 포함한 지방산으로의 가수분해로 구성되어있다. 불포화 지방산은 10-hydroxy- 와 10-keto-fatty acids를 거쳐ester acid로 전환이 된다. 이 과정은 hydratases와 재조합 대장균 기반의 alcohol dehydrogenase (ADH) 와a Baeyer-Villiger monooxygenase (BVMO)를 바탕으로 반응이 일어난다. Ester acid는 최종적으로 9-hydroxynonanoic acid 와 C9 carboxylic acids 로 가수분해 된다. Lipase와 hydratase는 기질과 중간 산물에 매우 높은 활성을 보이며, 적절한 반응을 위해 이를 연구하였다. Liapse-hydratase를 거쳐 Micrococcus luteus 유래의 ADH와 Pseudomonas putida KT2440 유래의 BVMO가 발현 되면 콩기름은 9-hydroxynonanoic acid, n-nonanoic acid, and n-non-3-enoic acid로 전환된다. 생물 전환은 5 g/L의 콩기름에서 8시간 안에 10.8 mM의 ω-hydroxynonanoic acid를 생산하게 했다. 더 나아가 재조합 대장균인 P. putida 유래의 alkJ 를 도입하여5 g/L 의 콩기름에서 5.5 mM의 azelaic acid를 생산해 낼 수 있었다. 이 결과들은 전 세포 생물전환을 통해 콩기름과 같은 원자재에서부터 고부가가치 산물인 ω-hydroxynonanoic acids 와 azelaic acid를 생산하는 결과를 나타낸다.