Chitosan degradation and associated changes in bacterial community structures in two contrasting soils
Chitosan degradation and associated changes in bacterial community structures in two contrasting soils
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两种对比土壤中壳聚糖的降解和细菌群落结构的相关变化
DOI：
10.1080/00380768.2014.1003965
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发表时间：
2015
影响因子：
2
通讯作者：
Akihiro Saito
中科院分区：
文献类型：
--
作者：
Ami Sawaguchi;Shouta Ono;Masaru Oomura;Kaori Inami;Yuta Kumeta;Kazuma Honda;Reiko Sameshima-Saito;Kazunori Sakamoto;Akikazu Ando;Akihiro Saito
壳聚糖是氨基葡萄糖的聚合物，是一种常用的天然多糖，可作为土壤改良剂。本文报道了壳聚糖在两种不同类型土壤中的降解及其对微生物的影响。建立了壳聚糖在土壤中添加量的测定方法，研究了壳聚糖粉末状在砂质和粉质土壤中的降解情况。在添加壳聚糖的砂质土中，即使在30 d后，壳聚糖含量和总碳(C)含量也没有显著变化。而在粉质土中，在25°C条件下，添加壳聚糖10 d后，壳聚糖含量下降到初始量（50 mg g - 1soil）的一半以下，30 d后似乎完全消耗。总碳和氮(N)含量也随着壳聚糖的减少而下降，而C/N比没有变化。在0.7 mg N g−1土壤中，添加壳聚糖后的11 d内，铵态氮逐渐增加。基于16S rRNA基因的聚合酶链反应(PCR)-变性梯度凝胶电泳（DGGE）分析表明，壳聚糖对粉质土壤细菌群落结构的影响较大，而对砂质土壤细菌群落结构的影响较小。DGGE核苷酸序列分析表明，壳聚糖在粉质土壤中添加壳聚糖后4 d内放线菌数量明显增加，放线菌属astretomycesh和kitasatosporse。从添加壳聚糖10 d后的粉质土壤中分离的8种壳聚糖降解细菌中，有7种根据16S rRNA基因的核苷酸序列被鉴定为best streptomcetes。其中AMI7和AMI10两株与PCR-DGGE分析结果核苷酸序列一致。这些数据强烈暗示，链霉菌属和可能的kitasatospora参与了壳聚糖在粉质土壤中的初始降解过程。这些属的存在和数量可能影响壳聚糖在土壤中的降解速率。
Chitosan, a polymer of glucosamine, is one of the natural polysaccharides which are used as soil-amendment materials. We report here chitosan degradation and the corresponding effects on microbes in two distinctive types of soil. Having established a method to measure amounts of chitosan which was added to soil, the degradation of powdered chitosan in a sandy or a silty soil was investigated. In the chitosan-added sandy soil, chitosan amount and total carbon (C) content did not significantly change even after 30 d. In contrast, chitosan added to the silty soil decreased to less than half of the initial amount (50 mg g−1soil) after 10 d incubation at 25°C and seemed to be completely consumed after 30 d. Total carbon and nitrogen (N) contents also declined according to the chitosan decrement, whereas the C/N ratio did not alter. Ammonium nitrogen was increasing over 0.7 mg N g−1soil, during the 11 d after the addition of chitosan. 16S rRNA gene-based polymerase chain reaction (PCR)-denaturant gradient gel electrophoresis (DGGE) analysis revealed that addition of chitosan caused drastic alteration of bacterial community structure in the silty soil, in contrast to fewer changes in the sandy soil. Nucleotide sequence analysis following DGGE revealed that actinobacteria belonging to generaStreptomycesandKitasatosporastrongly increased within 4 d after the addition of chitosan to the silty soil. Seven out of eight chitosan-degrading bacteria, isolated from the silty soil 10 d after the addition of chitosan, were identified to beStreptomycetes, based on the nucleotide sequence of the 16S rRNA gene. Among them, two strains, AMI7 and AMI10, exhibited identical nucleotide sequences with those detected in the PCR-DGGE analysis. The data strongly implied that those atcinobacterial genera,Streptomycesand probablyKitasatospora, are involved in the initial degradation process of chitosan in the silty soil. The presence and quantity of these genera may influence the chitosan degradation rate in soil.