Regar Raj Kumar, Singh Deeksha, Gaur Vivek Kumar, Thakur Ravindra Singh, Manickam Natesan
Environmental Biotechnology Laboratory, Environmental Toxicology Group, CSIR-Indian Institute of Toxicology Research, Vishvigyan Bhawan, 31, Mahatma Gandhi Marg, Lucknow, 226001, Uttar Pradesh, India.
Drug Standardisation Unit, Dr. D.P. Rastogi Central Research Institute for Homoeopathy, Noida, 201301, Uttar Pradesh, India.
Environ Sci Pollut Res Int. 2023 Apr;30(18):51770-51781. doi: 10.1007/s11356-023-25955-0. Epub 2023 Feb 23.
Indole is a nitrogenous heterocyclic aromatic pollutant often detected in various environments. An efficient indole degrading bacterium strain IITR89 was isolated from River Cauvery, India, and identified as Alcaligenes faecalis subsp. phenolicus. The bacterium was found to degrade ~ 95% of 2.5 mM (293.75 mg/L) of indole within 18 h utilizing it as a sole carbon and energy source. Based on metabolite identification, the metabolic route of indole degradation is indole → (indoxyl) → isatin → (anthranilate) → salicylic acid → (catechol) → (Acetyl-CoA) → and further entering into TCA cycle. Genome sequencing of IITR89 revealed the presence of gene cluster dmpKLMNOP, encoding multicomponent phenol hydroxylase; andAbcd gene cluster, encoding anthranilate 1,2-dioxygenase ferredoxin subunit (andAb), anthranilate 1,2-dioxygenase large subunit (andAc), and anthranilate 1,2-dioxygenase small subunit (andAd); nahG, salicylate hydroxylase; catA, catechol 1,2-dioxygenase; catB, cis, cis-muconate cycloisomerase; and catC, muconolactone D-isomerase which play an active role in indole degradation. The findings strongly support the degradation potential of strain IITR89 and its possible application for indole biodegradation.
吲哚是一种含氮杂环芳香污染物，常在各种环境中被检测到。从印度卡弗里河分离出一株高效降解吲哚的细菌菌株IITR89，并鉴定为粪产碱杆菌酚亚种。该细菌被发现能够在18小时内将2.5 mM（293.75 mg/L）的吲哚降解约95%，并将其作为唯一的碳源和能源。基于代谢产物鉴定，吲哚的代谢途径为吲哚→（吲哚酚）→异吲哚酮→（邻氨基苯甲酸）→水杨酸→（儿茶酚）→（乙酰辅酶A）→并进一步进入三羧酸循环。IITR89的基因组测序显示存在编码多组分酚羟化酶的基因簇dmpKLMNOP；以及编码邻氨基苯甲酸1,2-双加氧酶铁氧化还原蛋白亚基（andAb）、邻氨基苯甲酸1,2-双加氧酶大亚基（andAc）和邻氨基苯甲酸1,2-双加氧酶小亚基（andAd）的Abcd基因簇；nahG，水杨酸羟化酶；catA，儿茶酚1,2-双加氧酶；catB，顺,顺-粘康酸环异构酶；以及catC，粘康酸内酯D-异构酶，它们在吲哚降解中发挥着积极作用。这些发现有力地支持了菌株IITR89的降解潜力及其在吲哚生物降解中的可能应用。
