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Diversity and functional significance of cellulolytic microbes living in termite, pill-bug and stem-borer guts.

Bashir Z, Kondapalli VK, Adlakha N, Sharma A, Bhatnagar RK, Chandel G, Yazdani SS - Sci Rep (2013)

Bottom Line: Most of the carboxymethylcellulase positive strains also hydrolysed other amorphous substrates such as xylan, locust bean gum and β-D-glucan.Two strains, A11 and A21, demonstrated significant activity towards Avicel and p-nitrophenyl-β-D-cellobiose, indicating that they express cellobiohydrolase.These results provide insight into the co-existence of symbionts in the guts of arthropods and their possible exploitation for the production of fuels and chemicals derived from plant biomass.

View Article: PubMed Central - PubMed

Affiliation: Synthetic Biology and Biofuels Group, Aruna Asaf Ali Marg, New Delhi, India.

ABSTRACT
Arthropods living on plants are able to digest plant biomass with the help of microbial flora in their guts. This study considered three arthropods from different niches - termites, pill-bugs and yellow stem-borers - and screened their guts for cellulase producing microbes. Among 42 unique cellulase-producing strains, 50% belonged to Bacillaceae, 26% belonged to Enterobacteriaceae, 17% belonged to Microbacteriaceae, 5% belonged to Paenibacillaceae and 2% belonged to Promicromonosporaceae. The distribution of microbial families in the three arthropod guts reflected differences in their food consumption habits. Most of the carboxymethylcellulase positive strains also hydrolysed other amorphous substrates such as xylan, locust bean gum and β-D-glucan. Two strains, A11 and A21, demonstrated significant activity towards Avicel and p-nitrophenyl-β-D-cellobiose, indicating that they express cellobiohydrolase. These results provide insight into the co-existence of symbionts in the guts of arthropods and their possible exploitation for the production of fuels and chemicals derived from plant biomass.

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Quantitative assessment of the enzymatic activities of extracellular fractions against amorphous polysaccharides.All bacterial strains that were found to be cellulase positive by the agar plate assay were grown in liquid medium, and their extracellular fractions were tested for the hydrolysis of various substrates. Each graph indicates the substrate. Black bars represent strains that exhibited significantly higher activities compared to the negative controls, while white bars represent negative strains. The data represent the average and standard deviation of two different assays.
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f4: Quantitative assessment of the enzymatic activities of extracellular fractions against amorphous polysaccharides.All bacterial strains that were found to be cellulase positive by the agar plate assay were grown in liquid medium, and their extracellular fractions were tested for the hydrolysis of various substrates. Each graph indicates the substrate. Black bars represent strains that exhibited significantly higher activities compared to the negative controls, while white bars represent negative strains. The data represent the average and standard deviation of two different assays.

Mentions: Quantitative assessments of the hydrolytic activities in both the extracellular and cell-associated fractions enabled us to analyse their relative contributions to biomass degradation (Figure 4, 5 and 6). The majority of strains secreted high quantities of enzymes specific for amorphous polymers such as CMC, xylan, locust bean gum and barley β-D-glucan (Figure 4). Relatively fewer strains produced enzymes that were able to hydrolyse significant amounts of crystalline polymers such as Avicel and rice straw (Figure 5D, 6A and 6D). The strains hydrolysing the greatest amounts of rice straw were A11, A18, A21, A22, S2 and U8 (Figure 5D and 6D), while strains A11, A17, A21, A24, U5 and U10 hydrolysed Avicel (Figure 6A). Enzymes secreted from strains A11 and A21 also hydrolysed pNPC, indicating that these strains might produce either cellobiohydrolase or processive endoglucanase (Figure 5B). None of the cell bound fractions from any of the strains hydrolysed pNPC. Among β-glucosidase producers, a distinct set of strains exhibited extracellular and cell-associated β-glucosidase activity (Figure 5A and Figure 6B). Only three strains, A11, A19 and U8, produced extracellular β-xylosidase (Figure 5C). The remaining xylosidase producers expressed the β-xylosidase enzyme intracellularly (Figure 6C).


Diversity and functional significance of cellulolytic microbes living in termite, pill-bug and stem-borer guts.

Bashir Z, Kondapalli VK, Adlakha N, Sharma A, Bhatnagar RK, Chandel G, Yazdani SS - Sci Rep (2013)

Quantitative assessment of the enzymatic activities of extracellular fractions against amorphous polysaccharides.All bacterial strains that were found to be cellulase positive by the agar plate assay were grown in liquid medium, and their extracellular fractions were tested for the hydrolysis of various substrates. Each graph indicates the substrate. Black bars represent strains that exhibited significantly higher activities compared to the negative controls, while white bars represent negative strains. The data represent the average and standard deviation of two different assays.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3757366&req=5

f4: Quantitative assessment of the enzymatic activities of extracellular fractions against amorphous polysaccharides.All bacterial strains that were found to be cellulase positive by the agar plate assay were grown in liquid medium, and their extracellular fractions were tested for the hydrolysis of various substrates. Each graph indicates the substrate. Black bars represent strains that exhibited significantly higher activities compared to the negative controls, while white bars represent negative strains. The data represent the average and standard deviation of two different assays.
Mentions: Quantitative assessments of the hydrolytic activities in both the extracellular and cell-associated fractions enabled us to analyse their relative contributions to biomass degradation (Figure 4, 5 and 6). The majority of strains secreted high quantities of enzymes specific for amorphous polymers such as CMC, xylan, locust bean gum and barley β-D-glucan (Figure 4). Relatively fewer strains produced enzymes that were able to hydrolyse significant amounts of crystalline polymers such as Avicel and rice straw (Figure 5D, 6A and 6D). The strains hydrolysing the greatest amounts of rice straw were A11, A18, A21, A22, S2 and U8 (Figure 5D and 6D), while strains A11, A17, A21, A24, U5 and U10 hydrolysed Avicel (Figure 6A). Enzymes secreted from strains A11 and A21 also hydrolysed pNPC, indicating that these strains might produce either cellobiohydrolase or processive endoglucanase (Figure 5B). None of the cell bound fractions from any of the strains hydrolysed pNPC. Among β-glucosidase producers, a distinct set of strains exhibited extracellular and cell-associated β-glucosidase activity (Figure 5A and Figure 6B). Only three strains, A11, A19 and U8, produced extracellular β-xylosidase (Figure 5C). The remaining xylosidase producers expressed the β-xylosidase enzyme intracellularly (Figure 6C).

Bottom Line: Most of the carboxymethylcellulase positive strains also hydrolysed other amorphous substrates such as xylan, locust bean gum and β-D-glucan.Two strains, A11 and A21, demonstrated significant activity towards Avicel and p-nitrophenyl-β-D-cellobiose, indicating that they express cellobiohydrolase.These results provide insight into the co-existence of symbionts in the guts of arthropods and their possible exploitation for the production of fuels and chemicals derived from plant biomass.

View Article: PubMed Central - PubMed

Affiliation: Synthetic Biology and Biofuels Group, Aruna Asaf Ali Marg, New Delhi, India.

ABSTRACT
Arthropods living on plants are able to digest plant biomass with the help of microbial flora in their guts. This study considered three arthropods from different niches - termites, pill-bugs and yellow stem-borers - and screened their guts for cellulase producing microbes. Among 42 unique cellulase-producing strains, 50% belonged to Bacillaceae, 26% belonged to Enterobacteriaceae, 17% belonged to Microbacteriaceae, 5% belonged to Paenibacillaceae and 2% belonged to Promicromonosporaceae. The distribution of microbial families in the three arthropod guts reflected differences in their food consumption habits. Most of the carboxymethylcellulase positive strains also hydrolysed other amorphous substrates such as xylan, locust bean gum and β-D-glucan. Two strains, A11 and A21, demonstrated significant activity towards Avicel and p-nitrophenyl-β-D-cellobiose, indicating that they express cellobiohydrolase. These results provide insight into the co-existence of symbionts in the guts of arthropods and their possible exploitation for the production of fuels and chemicals derived from plant biomass.

Show MeSH