Department of Agricultural Microbiology, Directorate of Natural Resource Management, Agricultural College and Research Institute, Coimbatore, 641003, India.
Centre for Post-Harvest Technology, Agricultural Engineering College and Research Institute, Coimbatore, 641003, India.
Folia Microbiol (Praha). 2024 Apr;69(2):395-405. doi: 10.1007/s12223-023-01080-w. Epub 2023 Jul 28.
Sulfur-oxidizing bacteria (SOB) are versatile microorganisms known for their ability to oxidize various reduced sulfur compounds, namely, elemental sulfur (S), hydrogen sulfide (HS), tetrathionate (SO), and trithionate (SO) to sulfate (SO). In this study, out of twelve SOB isolates from rice rhizosphere, five were screened based on their sulfur oxidation potential, viz., SOB1, SOB2, SOB3, SOB4, and SOB5, and were identified as Ochrobactrum soli SOB1, Achromobacter xylosoxidans SOB2, Stenotrophomonas maltophilia SOB3, Brucella tritici SOB4, and Stenotrophomonas pavanii SOB5, respectively. All the isolates displayed chemolithotrophic nutritional mode by consuming thiosulfate and accumulating trithionate and tetrathionate in the growth medium which is ultimately oxidized to sulfate. The strains were authenticated with the production of thiosulfate oxidizing enzymes such as rhodanese and sulfite oxidase. Despite their tendency to oxidize reduced sulfur compounds, B. tritici SOB4 and S. pavanii SOB5 were also found to possess phosphate and zinc solubilization potential, acetic acid, and indole acetic acid (IAA) production and 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity. The presence of sulfanyl (R-SH) groups was noticed in the A. xylosoxidans SOB2. Elemental sulfur conversion into sulfate was noted in the S. maltophilia SOB3, and hydrogen sulfide conversion into sulfate was observed in the Ochromobacter soli SOB1. Sulfur oxidation potential coupled with beneficial properties of the isolates widen the knowledge on SOB.
硫氧化菌（SOB）是一种多功能微生物，以能够氧化各种还原态硫化合物而闻名，即元素硫（S）、硫化氢（HS）、连四硫酸盐（SO）和连五硫酸盐（SO）为硫酸盐（SO）。在这项研究中，从水稻根际中分离出的十二种 SOB 分离物中，根据其硫氧化潜力筛选出五种，即 SOB1、SOB2、SOB3、SOB4 和 SOB5，并分别鉴定为固氮硫杆菌 SOB1、木糖氧化无色杆菌 SOB2、嗜麦芽窄食单胞菌 SOB3、布鲁氏菌 SOB4 和寡养单胞菌 SOB5。所有分离物均通过消耗硫代硫酸盐并在生长培养基中积累连四硫酸盐和连五硫酸盐来显示化能自养营养模式，最终将其氧化为硫酸盐。这些菌株通过产生硫代硫酸盐氧化酶（如硫氰酸酶和亚硫酸氧化酶）得到验证。尽管 B. tritici SOB4 和 S. pavanii SOB5 倾向于氧化还原态硫化合物，但它们也被发现具有磷酸盐和锌的溶解能力、醋酸和吲哚乙酸（IAA）的产生以及 1-氨基环丙烷-1-羧酸（ACC）脱氨酶活性。木糖氧化无色杆菌 SOB2 中存在硫烷（R-SH）基团。嗜麦芽窄食单胞菌 SOB3 将元素硫转化为硫酸盐，固氮硫杆菌 SOB1 将硫化氢转化为硫酸盐。硫氧化潜力加上分离物的有益特性，拓宽了对 SOB 的认识。
