Yu Z, Stewart G R, Mohn W W
Department of Microbiology and Immunology and Pulp and Paper Centre, University of British Columbia, Vancouver, British Columbia V6T 1Z3 Canada.
Appl Environ Microbiol. 2000 Dec;66(12):5148-54. doi: 10.1128/AEM.66.12.5148-5154.2000.
Resin acids are tricyclic terpenoids occurring naturally in trees. We investigated the occurrence of resin acid-degrading bacteria on the Arctic tundra near the northern coast of Ellesmere Island (82 degrees N, 62 degrees W). According to most-probable-number assays, resin acid degraders were abundant (10(3) to 10(4) propagules/g of soil) in hydrocarbon-contaminated soils, but they were undetectable (<3 propagules/g of soil) in pristine soils from the nearby tundra. Plate counts indicated that the contaminated and the pristine soils had similar populations of heterotrophs (10(6) to 10(7) propagules/g of soil). Eleven resin acid-degrading bacteria belonging to four phylogenetically distinct groups were enriched and isolated from the contaminated soils, and representative isolates of each group were further characterized. Strains DhA-91, IpA-92, and IpA-93 are members of the genus Pseudomonas. Strain DhA-95 is a member of the genus Sphingomonas. All four strains are psychrotolerant, with growth temperature ranges of 4 degrees C to 30 degrees C (DhA-91 and DhA-95) or 4 degrees C to 22 degrees C (IpA-92 and IpA-93) and with optimum temperatures of 15 to 22 degrees C. Strains DhA-91 and DhA-95 grew on the abietanes, dehydroabietic and abietic acids, but not on the pimaranes, isopimaric and pimaric acids. Strains IpA-92 and IpA-93 grew on the pimaranes but not the abietanes. All four strains grew on either aliphatic or aromatic hydrocarbons, which is unusual for described resin acid degraders. Eleven mesophilic resin acid degraders did not use hydrocarbons, with the exception of two Mycobacterium sp. strains that used aliphatic hydrocarbons. We conclude that hydrocarbon contamination in Arctic tundra soil indirectly selected for resin acid degraders, selecting for hydrocarbon degraders that coincidentally use resin acids. Psychrotolerant resin acid degraders are likely important in the global carbon cycle and may have applications in biotreatment of pulp and paper mill effluents.
树脂酸是树木中天然存在的三环萜类化合物。我们调查了埃尔斯米尔岛北海岸附近北极苔原（北纬82度，西经62度）上树脂酸降解细菌的存在情况。根据最大可能数分析法，在受碳氢化合物污染的土壤中，树脂酸降解菌数量丰富（每克土壤中有10³至10⁴个繁殖体），但在附近苔原的原始土壤中无法检测到（每克土壤中少于3个繁殖体）。平板计数表明，受污染土壤和原始土壤中的异养菌数量相似（每克土壤中有10⁶至10⁷个繁殖体）。从受污染土壤中富集并分离出了11株属于4个系统发育不同组的树脂酸降解细菌，并对每组的代表性菌株进行了进一步表征。菌株DhA - 91、IpA - 92和IpA - 93属于假单胞菌属。菌株DhA - 95属于鞘氨醇单胞菌属。所有4株菌株均耐低温，生长温度范围为4℃至30℃（DhA - 91和DhA - 95）或4℃至22℃（IpA - 92和IpA - 93），最适温度为15至22℃。菌株DhA - 91和DhA - 95能在枞酸型酸、脱氢枞酸和枞酸上生长，但不能在海松酸型酸、异海松酸和海松酸上生长。菌株IpA - 92和IpA - 93能在海松酸型酸上生长，但不能在枞酸型酸上生长。所有4株菌株都能在脂肪族或芳香族碳氢化合物上生长，这对于已描述的树脂酸降解菌来说并不常见。11株嗜温树脂酸降解菌除了两株能利用脂肪族碳氢化合物的分枝杆菌属菌株外，都不利用碳氢化合物。我们得出结论，北极苔原土壤中的碳氢化合物污染间接选择了树脂酸降解菌，选择了碰巧能利用树脂酸的碳氢化合物降解菌。耐低温的树脂酸降解菌可能在全球碳循环中很重要，并且可能在纸浆和造纸厂废水的生物处理中有应用。
