Microbial conversion of oleic acid (1) to form value-added industrial products has gained increasing scientific and economic interest. So far, the production of natural lactones with flavor and fragrance properties from fatty acids by non-genetically modified organisms (non-GMO) involves whole cells of bacteria catalyzing the hydration of unsaturated fatty acids as well as yeast strains responsible for further β-oxidation processes. Development of a non-GMO process, involving a sole strain possessing both enzymatic activities, significantly lowers the costs of the process and constitutes a better method from the customers’ point of view regarding biosafety issues. Twenty bacteria from the genus of Bacillus, Comamonas, Dietzia, Gordonia, Micrococcus, Pseudomonas, Rhodococcus and Streptomyces were screened for oxidative functionalization of oleic acid (1). Micrococcus luteus PCM525 was selected as the sole strain catalyzing the one-pot transformation of oleic acid (1) into natural valuable peach and strawberry-flavored γ-dodecalactone (6) used in the food, beverage, cosmetics and pharmaceutical industries. Based on the identified products formed during the process of biotransformation, we clearly established a pathway showing that oleic acid (1) is hydrated to 10-hydroxystearic acid (2), then oxidized to 10-ketostearic acid (3), giving 4-ketolauric acid (4) after three cycles of β-oxidation, which is subsequently reduced and cyclized to γ-dodecalactone (6) (Scheme 1). Moreover, three other strains (Rhodococcus erythropolis DSM44534, Rhodococcus ruber PCM2166, Dietzia sp. DSM44016), with high concomitant activities of oleate hydratase and alcohol dehydrogenase, were identified as efficient producers of 10-ketostearic acid (3), which can be used in lubricant and detergent formulations. Considering the prevalence of γ-dodecalactone (6) and 10-ketostearic acid (3) applications and the economic benefits of sustainable management, microbial bioconversion of oleic acid (1) is an undeniably attractive approach.

中文翻译：

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油酸的细菌生物转化：藤黄微球菌培养中γ-十二内酯和10-酮硬脂酸形成的新发现


油酸（1）的微生物转化形成增值工业产品已引起越来越多的科学和经济兴趣。到目前为止，通过非转基因生物（non-GMO）从脂肪酸生产具有风味和香味特性的天然内酯涉及催化不饱和脂肪酸水合的细菌全细胞以及负责进一步β-氧化的酵母菌株流程。开发一种非转基因工艺，涉及具有两种酶活性的单一菌株，可以显着降低工艺成本，并且从客户的角度来看，在生物安全问题上是一种更好的方法。对来自芽孢杆菌属、丛毛单胞菌属、迪茨氏菌属、戈尔登氏菌属、微球菌属、假单胞菌属、红球菌属和链霉菌属的 20 种细菌进行了油酸氧化功能化筛选 (1)。选择藤黄微球菌PCM525作为唯一菌株催化油酸（1）一锅转化为用于食品、饮料、化妆品和制药行业的天然有价值的桃子和草莓味γ-十二内酯（6）。根据生物转化过程中形成的已鉴定产物，我们清楚地建立了一条途径，表明油酸 (1) 水合为 10-羟基硬脂酸 (2)，然后氧化为 10-酮硬脂酸 (3)，得到 4-酮月桂酸经过三个循环的 β-氧化后生成酸 (4)，随后被还原并环化为 γ-十二内酯 (6)（方案 1）。此外，其他三种菌株（红平红球菌 DSM44534、红球菌 PCM2166、迪茨氏菌属 sp. DSM44016) 具有高油酸水合酶和乙醇脱氢酶的伴随活性，被确定为 10-酮硬脂酸 (3) 的高效生产者，可用于润滑剂和洗涤剂配方。考虑到 γ-十二内酯 (6) 和 10-酮硬脂酸 (3) 应用的普遍性以及可持续管理的经济效益，油酸 (1) 的微生物生物转化无疑是一种有吸引力的方法。