Fujii Katsuhiko, Takeshi Kyoko
Department of Agriculture, Yamaguchi University, Yoshida, Yamaguchi, Japan.
J Appl Microbiol. 2007 Dec;103(6):2713-20. doi: 10.1111/j.1365-2672.2007.03529.x. Epub 2007 Sep 10.
Coffee residue is an agricultural waste which inhibits the growth of several crops. Therefore coffee residue-degrading microbes in soil were screened, isolated and characterized.
Forty isolates were obtained after enrichment culture of soil samples. Seven strains (fast degraders) showed strong degrading activity, while 18 strains (slow degraders) showed weak degrading activity. DNA analysis suggested that the fast degraders are Penicillium, and the slow degraders are Penicillium, Trichoderma/Hypocrea, Fusarium/Gibberella, Phaeoacremonium/Togninia or Acidocella. The all fast degraders are cellulolytic, mannolytic and pectinolytic.
Although it is generally thought that fungi such as Trichoderma contribute largely to aerobic degradation of cellulosic biomass, our data suggested that Penicillium overwhelms them in coffee residue degradation. It was implied that polysaccharides in coffee residue are not degraded independently by different microbes, but degraded simultaneously by strains with cellulolytic, mannolytic and pectinolytic activity. Since there is no report of an ascomycete possessing all the three enzyme activities, the fast degraders are ecologically important and have the potential to be used as producers of the costly enzymes from agricultural wastes.
The present results advance our understanding of microbial degradation of a phytotoxic agricultural waste, and offer a new tool for recycling it.
咖啡渣是一种农业废弃物，会抑制多种作物的生长。因此，对土壤中能降解咖啡渣的微生物进行了筛选、分离和鉴定。
对土壤样品进行富集培养后获得了40株分离菌。7株（快速降解菌）表现出较强的降解活性，而18株（慢速降解菌）表现出较弱的降解活性。DNA分析表明，快速降解菌为青霉属，慢速降解菌为青霉属、木霉属/肉座菌属、镰刀菌属/赤霉属、拟暗梗孢霉属/托尼亚菌属或嗜酸菌属。所有快速降解菌都具有纤维素分解、甘露糖分解和果胶分解能力。
尽管一般认为木霉属等真菌在纤维素生物质的好氧降解中起主要作用，但我们的数据表明，在咖啡渣降解方面青霉属比它们更具优势。这意味着咖啡渣中的多糖不是由不同微生物独立降解的，而是由具有纤维素分解、甘露糖分解和果胶分解活性的菌株同时降解的。由于尚无关于具有所有这三种酶活性的子囊菌的报道，这些快速降解菌在生态上具有重要意义，并且有潜力用作从农业废弃物中生产昂贵酶的菌株。
目前的结果增进了我们对一种具有植物毒性的农业废弃物微生物降解的理解，并为其回收利用提供了一种新工具。
