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Isolation of cellulolytic bacteria from the intestine of Diatraea saccharalis larvae and evaluation of their capacity to degrade sugarcane biomass.

Dantur KI, Enrique R, Welin B, Castagnaro AP - AMB Express (2015)

Bottom Line: Bacterial growth on sugarcane biomass as well as extracellular endo-glucanase activity induced on soluble cellulose was found to be highest in species belonging to genera Bacillus and Klebsiella.Good cellulolytic activity correlated with high extracellular protein concentrations.In addition, scanning microscopy studies revealed attachment of cellulolytic strains to different sugarcane substrates.

View Article: PubMed Central - PubMed

Affiliation: Estación Experimental Agroindustrial Obispo Colombres (EEAOC) - Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Tecnología Agroindustrial del Noroeste Argentino (ITANOA), 3150 William Cross Av., Las Talitas, PC T4101XAC Tucumán Argentina.

ABSTRACT
As a strategy to find efficient lignocellulose degrading enzymes/microorganisms for sugarcane biomass pretreatment purposes, 118 culturable bacterial strains were isolated from intestines of sugarcane-fed larvae of the moth Diatraea saccharalis. All strains were tested for cellulolytic activity using soluble carboxymethyl cellulose (CMC) degrading assays or by growing bacteria on sugarcane biomass as sole carbon sources. Out of the 118 strains isolated thirty eight were found to possess cellulose degrading activity and phylogenetic studies of the 16S rDNA sequence revealed that all cellulolytic strains belonged to the phyla γ-Proteobacteria, Actinobacteria and Firmicutes. Within the three phyla, species belonging to five different genera were identified (Klebsiella, Stenotrophomonas, Microbacterium, Bacillus and Enterococcus). Bacterial growth on sugarcane biomass as well as extracellular endo-glucanase activity induced on soluble cellulose was found to be highest in species belonging to genera Bacillus and Klebsiella. Good cellulolytic activity correlated with high extracellular protein concentrations. In addition, scanning microscopy studies revealed attachment of cellulolytic strains to different sugarcane substrates. The results of this study indicate the possibility to find efficient cellulose degrading enzymes and microorganisms from intestines of insect larvae feeding on sugarcane and their possible application in industrial processing of sugarcane biomass such as second generation biofuel production.

No MeSH data available.


Related in: MedlinePlus

Bacterial adhesion to sugarcane harvest residues. Scanning electron microscopy (SEM) images showing bacterial adherence to plant fibers originating from sugarcane HT. Left image, rod-shaped Klebsiella oxytoca strain Kd70 TUC-EEAOC. Right image, diplococci of the Enterococcus casseliflavus strain Kd7 TUC-EEAOC. White bars shown in the left bottom corners of both figures indicate 2 μm.
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Fig5: Bacterial adhesion to sugarcane harvest residues. Scanning electron microscopy (SEM) images showing bacterial adherence to plant fibers originating from sugarcane HT. Left image, rod-shaped Klebsiella oxytoca strain Kd70 TUC-EEAOC. Right image, diplococci of the Enterococcus casseliflavus strain Kd7 TUC-EEAOC. White bars shown in the left bottom corners of both figures indicate 2 μm.

Mentions: An important step for efficient bacterial hydrolysis of cellulose and hemicellulose is the adhesion of the bacteria to the substrate fiber. To verify that bacterial isolates from the intestine of D. saccharalis can attach to sugarcane biomass material, scanning electron microscopy studies were performed on bagasse and HT incubated with one Gram-positive (Enterococcus) and one Gram-negative bacterium (Klebsiella), respectively. As can be seen in Figure 5 both strains attach firmly to both sugarcane bagasse (left) and HT fibers (right). The Klebsiella oxytoca strain Kd70 TUC-EEAOC attaches as single rod-shaped bacterial cells while Enterococcus casseliflavus strain Kd7 TUC-EEAOC is characteristically found attached in cell-pairs.Figure 5


Isolation of cellulolytic bacteria from the intestine of Diatraea saccharalis larvae and evaluation of their capacity to degrade sugarcane biomass.

Dantur KI, Enrique R, Welin B, Castagnaro AP - AMB Express (2015)

Bacterial adhesion to sugarcane harvest residues. Scanning electron microscopy (SEM) images showing bacterial adherence to plant fibers originating from sugarcane HT. Left image, rod-shaped Klebsiella oxytoca strain Kd70 TUC-EEAOC. Right image, diplococci of the Enterococcus casseliflavus strain Kd7 TUC-EEAOC. White bars shown in the left bottom corners of both figures indicate 2 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4385043&req=5

Fig5: Bacterial adhesion to sugarcane harvest residues. Scanning electron microscopy (SEM) images showing bacterial adherence to plant fibers originating from sugarcane HT. Left image, rod-shaped Klebsiella oxytoca strain Kd70 TUC-EEAOC. Right image, diplococci of the Enterococcus casseliflavus strain Kd7 TUC-EEAOC. White bars shown in the left bottom corners of both figures indicate 2 μm.
Mentions: An important step for efficient bacterial hydrolysis of cellulose and hemicellulose is the adhesion of the bacteria to the substrate fiber. To verify that bacterial isolates from the intestine of D. saccharalis can attach to sugarcane biomass material, scanning electron microscopy studies were performed on bagasse and HT incubated with one Gram-positive (Enterococcus) and one Gram-negative bacterium (Klebsiella), respectively. As can be seen in Figure 5 both strains attach firmly to both sugarcane bagasse (left) and HT fibers (right). The Klebsiella oxytoca strain Kd70 TUC-EEAOC attaches as single rod-shaped bacterial cells while Enterococcus casseliflavus strain Kd7 TUC-EEAOC is characteristically found attached in cell-pairs.Figure 5

Bottom Line: Bacterial growth on sugarcane biomass as well as extracellular endo-glucanase activity induced on soluble cellulose was found to be highest in species belonging to genera Bacillus and Klebsiella.Good cellulolytic activity correlated with high extracellular protein concentrations.In addition, scanning microscopy studies revealed attachment of cellulolytic strains to different sugarcane substrates.

View Article: PubMed Central - PubMed

Affiliation: Estación Experimental Agroindustrial Obispo Colombres (EEAOC) - Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Tecnología Agroindustrial del Noroeste Argentino (ITANOA), 3150 William Cross Av., Las Talitas, PC T4101XAC Tucumán Argentina.

ABSTRACT
As a strategy to find efficient lignocellulose degrading enzymes/microorganisms for sugarcane biomass pretreatment purposes, 118 culturable bacterial strains were isolated from intestines of sugarcane-fed larvae of the moth Diatraea saccharalis. All strains were tested for cellulolytic activity using soluble carboxymethyl cellulose (CMC) degrading assays or by growing bacteria on sugarcane biomass as sole carbon sources. Out of the 118 strains isolated thirty eight were found to possess cellulose degrading activity and phylogenetic studies of the 16S rDNA sequence revealed that all cellulolytic strains belonged to the phyla γ-Proteobacteria, Actinobacteria and Firmicutes. Within the three phyla, species belonging to five different genera were identified (Klebsiella, Stenotrophomonas, Microbacterium, Bacillus and Enterococcus). Bacterial growth on sugarcane biomass as well as extracellular endo-glucanase activity induced on soluble cellulose was found to be highest in species belonging to genera Bacillus and Klebsiella. Good cellulolytic activity correlated with high extracellular protein concentrations. In addition, scanning microscopy studies revealed attachment of cellulolytic strains to different sugarcane substrates. The results of this study indicate the possibility to find efficient cellulose degrading enzymes and microorganisms from intestines of insect larvae feeding on sugarcane and their possible application in industrial processing of sugarcane biomass such as second generation biofuel production.

No MeSH data available.


Related in: MedlinePlus