Community composition and cellulase activity of cellulolytic bacteria from forest soils planted with broad-leaved deciduous and evergreen trees

Abstract

Cellulolytic bacteria in forest soil provide carbon sources to improve the soil fertility and sustain the nutrient balance of the forest ecological system through the decomposition of cellulosic remains. These bacteria can also be utilized for the biological conversion of biomass into renewable biofuels. In this study, the community compositions and activities of cellulolytic bacteria in the soils of forests planted with broad-leaved deciduous (Chang Qing Garden, CQG) and broad-leaved evergreen (Forest Park, FP) trees in Wuhan, China were resolved through restriction fragment length polymorphism (RFLP) and sequencing analysis of the 16S rRNA gene. All of the isolates exhibited 35 RFLP fingerprint patterns and were clustered into six groups at a similarity level of 50 %. The phylogeny analysis based on the 16S rRNA gene sequence revealed that these RFLP groups could be clustered into three phylogenetic groups and further divided into six subgroups at a higher resolution. Group I consists of isolates from Bacillus cereus, Bacillus subtilis complex (I-A) and from Paenibacillus amylolyticus-related complex (I-B) and exhibited the highest cellulase activity among all of the cellulolytic bacteria isolates. Cluster II consists of isolates belonging to Microbacterium testaceum (II-A), Chryseobacterium indoltheticum (II-B), and Flavobacterium pectinovorum and the related complex (II-C). Cluster III consists of isolates belonging to Pseudomonas putida-related species. The community shift with respect to the plant species and the soil properties was evidenced by the phylogenetic composition of the communities. Groups I-A and I-B, which account for 36.0 % of the cellulolytic communities in the CQG site, are the dominant groups (88.4 %) in the FP site. Alternatively, the ratio of the bacteria belonging to group III (P. putida-related isolates) shifted from 28.0 % in CQG to 4.0 % in FP. The soil nutrient analysis revealed that the CQG site planted with deciduous broad-leaved trees has a richer organic nutrient (total organic carbon and total nitrogen) than the FP site planted with evergreen broad-leaved trees. Against this background, the population density and the diversity of cellulolytic bacteria in the CQG site are clearly higher than those in the FP site, and the latter was dominated with high-cellulase-activity Bacillus- and Paenibacillus-related bacteria. The canonical correspondence analysis further indicated that the distribution of these groups is correlated with the FP site, whereas groups II and III are correlated with the organic nutrient-rich CQG site.

Concentration Ranges of Antibacterial Cations for Showing the Highest Antibacterial Efficacy but the Least Cytotoxicity against Mammalian Cells: Implications for a New Antibacterial Mechanism

“…43 The agar gel electrophoresis profiles for direct analysis of genomic DNA are shown in Figure 4. The analysis of agar gel electrophoresis demonstrated that antibacterial metal ions could not induce the decomposability of genome DNA.…”

Long-Term Warming Alters Carbohydrate Degradation Potential in Temperate Forest Soils

“…Due to cultivation bias (82), phylogenetic correction is required to conclude increased probability of carbohydrate degradation ability (83), although many previous papers comparing the physiological capacity of bacteria isolated from different environments or under different conditions in the laboratory have failed to consider the potential need to correct for phylogenetic autocorrelation in their analysis (84–86). With this analysis of isolate physiology, we were able to establish that there is a trend toward increasing capacity of bacteria for degradation of cellulose and xylan with warming.…”

Cellulolytic Bacteria Associated with the Gut of Dendroctonus armandi Larvae (Coleoptera: Curculionidae: Scolytinae)

“…The cellulolytic activity of Paenibacillus was reported [34], and Okeke and Lu reported that Pseudoxanthomonas produced an array of cellulolytic-xylanolytic enzymes (filter paper cellulase, β-glucosidase, xylanase and β-xylosidase) and also assayed these activities [35]. Methylobacterium expressing β-1,4-endoglucanase was described [36], and an uncultured cellulolytic strain that is closely related to Sphingomonas was also found in the gut of the termite Zootermopsis angusticollis (Hagen) [37].…”