Dash Swati Sucharita, Gummadi Sathyanarayana N
Department of Biotechnology, Indian Institute of Technology-Madras, Chennai, 600 036, India.
Biotechnol Lett. 2006 Dec;28(24):1993-2002. doi: 10.1007/s10529-006-9196-2. Epub 2006 Sep 29.
Catabolism of caffeine (1,3,7-trimethylxanthine) in microorganisms commences via two possible mechanisms: demethylation and oxidation. Through the demethylation route, the major metabolite formed in fungi is theophylline (1,3-dimethylxanthine), whereas theobromine (3,7-dimethylxanthine) is the major metabolite in bacteria. In certain bacterial species, caffeine has also been oxidized directly to trimethyl uric acid in a single step. The conversion of caffeine to its metabolites is primarily brought about by N-demethylases (such as caffeine demethylase, theobromine demethylase and heteroxanthinedemethylase), caffeine oxidase and xanthine oxidase that are produced by several caffeine-degrading bacterial species such as Pseudomonas putida and species within the genera Alcaligenes, Rhodococcus and Klebsiella. Development of biodecaffeination techniques using these enzymes or using whole cells offers an attractive alternative to the present existing chemical and physical methods removal of caffeine, which are costly, toxic and non-specific to caffeine. This review mainly focuses on the biochemistry of microbial caffeine degradation, presenting recent advances and the potential biotechnological application of caffeine-degrading enzymes.
微生物中咖啡因（1,3,7 - 三甲基黄嘌呤）的分解代谢通过两种可能的机制开始：去甲基化和氧化。通过去甲基化途径，真菌中形成的主要代谢产物是茶碱（1,3 - 二甲基黄嘌呤），而细菌中的主要代谢产物是可可碱（3,7 - 二甲基黄嘌呤）。在某些细菌物种中，咖啡因也可以一步直接氧化为三甲基尿酸。咖啡因向其代谢产物的转化主要由几种降解咖啡因的细菌物种（如恶臭假单胞菌以及产碱菌属、红球菌属和克雷伯菌属中的物种）产生的N - 去甲基酶（如咖啡因去甲基酶、可可碱去甲基酶和杂黄嘌呤去甲基酶）、咖啡因氧化酶和黄嘌呤氧化酶引起。使用这些酶或全细胞开发生物脱咖啡因技术为目前现有的去除咖啡因的化学和物理方法提供了一种有吸引力的替代方案，这些化学和物理方法成本高、有毒且对咖啡因不具有特异性。本综述主要关注微生物咖啡因降解的生物化学，介绍咖啡因降解酶的最新进展和潜在的生物技术应用。
