Novel multispecies microbial consortia involved in lignocellulose and 5-hydroxymethylfurfural bioconversion
Novel multispecies microbial consortia involved in lignocellulose and 5-hydroxymethylfurfural bioconversion
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DOI：
10.1007/s00253-013-5253-7
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发表时间：
2014-03-01
影响因子：
5
通讯作者：
van Elsas, Jan Dirk
中科院分区：
文献类型：
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作者：
Jimenez, Diego Javier;Korenblum, Elisa;van Elsas, Jan Dirk
为了开发一种有针对性的宏基因组学方法来分析参与木质纤维素和呋烷化合物生物转化的新型多物种微生物群落，我们使用预处理或未经处理的麦秸作为碳和能量来源，进行了重复的顺序分批有氧富集培养。每次转移后，使用显微镜细胞计数检测到细菌的指数生长，表明底物正在被利用。在批处理中，最终细菌丰度从估计的5增加到8.7-9.5 log 16S rRNA基因拷贝数/ml。真菌繁殖体的丰度变化较大，在5.4 ~ 8.0 log ITS1 copies/ml之间。变性梯度凝胶电泳分析表明，两种处理下的菌群在6次转移后达到了近似的结构稳定。此外，真菌群落的结构受到底物处理的强烈影响。两种富集培养共分离出124株细菌。菌株最多的是Raoultella/Klebsiella属、Kluyvera属、Citrobacter属、Enterobacter属、Pseudomonas属、Acinetobacter属、Flavobacterium属和Arthrobacter属。从未处理和预处理的底物中分别获得的43株和11株菌株显示（半）纤维素水解活性（cmc酶和木聚糖酶），而96株菌株能够在7.5 mM 5-羟甲基糠醛中生长。通过一种新的碘化物氧化法检测，后者约50%表现出细胞外氧化还原酶活性。此外，还分离到与Coniochaeta、Plectosphaerella和Penicillium相关的（半）纤维素降解真菌菌株。从预处理过的麦秸中分离到一株毛孢菌。这两种新型细菌-真菌联合体是木质纤维素降解应用的起点。
To develop a targeted metagenomics approach for the analysis of novel multispecies microbial consortia involved in the bioconversion of lignocellulose and furanic compounds, we applied replicated sequential batch aerobic enrichment cultures with either pretreated or untreated wheat straw as the sources of carbon and energy. After each transfer, exponential growth of bacteria was detected using microscopic cell counts, indicating that the substrate was being utilized. In batch, the final bacterial abundances increased from an estimated 5 to 8.7-9.5 log 16S rRNA gene copy numbers/ml. The abundances of fungal propagules showed greater variation, i.e., between 5.4 and 8.0 log ITS1 copies/ml. Denaturing gradient gel electrophoresis analyses showed that the bacterial consortia in both treatments reached approximate structural stability after six transfers. Moreover, the structures of the fungal communities were strongly influenced by substrate treatment. A total of 124 bacterial strains were isolated from the two types of enrichment cultures. The most abundant strains were affiliated with the genera Raoultella/Klebsiella, Kluyvera, Citrobacter, Enterobacter, Pseudomonas, Acinetobacter, Flavobacterium and Arthrobacter. Totals of 43 and 11 strains obtained from the untreated and pretreated substrates, respectively, showed (hemi)cellulolytic activity (CMC-ase and xylanase), whereas 96 strains were capable of growth in 7.5 mM 5-hydroxymethylfurfural. About 50 % of the latter showed extracellular oxidoreductase activity as detected by a novel iodide oxidation method. Also, (hemi)cellulolytic fungal strains related to Coniochaeta, Plectosphaerella and Penicillium were isolated. One Trichosporon strain was isolated from pretreated wheat straw. The two novel bacterial-fungal consortia are starting points for lignocellulose degradation applications.