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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

Screening for sugarcane biomass degrading bacteria. A) Bacteria from the intestine of D. saccharalis were grown for 3 days on Petri dishes containing minimal medium supplemented with 0.5% (w/v) sugarcane bagasse as sole carbon source. After colonies had developed, plates were stained using Congo red dye to indicate cellulolytic activity of the colony. B) Bacterial strains showing cellulolytic activity on plates in A were purified and grown on Petri dishes containing CMC, which were later coloured with Congo red. The halo around bacterial colonies indicates total cellulolytic activity of the bacterial isolate.
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Fig1: Screening for sugarcane biomass degrading bacteria. A) Bacteria from the intestine of D. saccharalis were grown for 3 days on Petri dishes containing minimal medium supplemented with 0.5% (w/v) sugarcane bagasse as sole carbon source. After colonies had developed, plates were stained using Congo red dye to indicate cellulolytic activity of the colony. B) Bacterial strains showing cellulolytic activity on plates in A were purified and grown on Petri dishes containing CMC, which were later coloured with Congo red. The halo around bacterial colonies indicates total cellulolytic activity of the bacterial isolate.

Mentions: In order to isolate bacterial symbionts of the intestine of sugarcane-fed D. saccharalis, fifth instar larvae were collected in sugarcane production fields in the Province of Tucumán in the Northwest of Argentina. Intestines of larvae were immediately dissected and plated on agar plates containing a bacterial minimal growth medium supplemented either with glucose or sugarcane biomass in the form of bagasse or harvest trash (HT), as sole carbon source. From these initial plates 118 bacterial colonies were isolated showing preliminary cellulose degrading activity as deduced from halo formation around the bacterial colony when treated with Congo red (Figure 1A), eighty from glucose plates (1.2 × 108 colony forming units.ml-1) and thirty eight from the two lignocellulose substrate plates (2.0 × 105 colony forming units.ml-1).Figure 1


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)

Screening for sugarcane biomass degrading bacteria. A) Bacteria from the intestine of D. saccharalis were grown for 3 days on Petri dishes containing minimal medium supplemented with 0.5% (w/v) sugarcane bagasse as sole carbon source. After colonies had developed, plates were stained using Congo red dye to indicate cellulolytic activity of the colony. B) Bacterial strains showing cellulolytic activity on plates in A were purified and grown on Petri dishes containing CMC, which were later coloured with Congo red. The halo around bacterial colonies indicates total cellulolytic activity of the bacterial isolate.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Fig1: Screening for sugarcane biomass degrading bacteria. A) Bacteria from the intestine of D. saccharalis were grown for 3 days on Petri dishes containing minimal medium supplemented with 0.5% (w/v) sugarcane bagasse as sole carbon source. After colonies had developed, plates were stained using Congo red dye to indicate cellulolytic activity of the colony. B) Bacterial strains showing cellulolytic activity on plates in A were purified and grown on Petri dishes containing CMC, which were later coloured with Congo red. The halo around bacterial colonies indicates total cellulolytic activity of the bacterial isolate.
Mentions: In order to isolate bacterial symbionts of the intestine of sugarcane-fed D. saccharalis, fifth instar larvae were collected in sugarcane production fields in the Province of Tucumán in the Northwest of Argentina. Intestines of larvae were immediately dissected and plated on agar plates containing a bacterial minimal growth medium supplemented either with glucose or sugarcane biomass in the form of bagasse or harvest trash (HT), as sole carbon source. From these initial plates 118 bacterial colonies were isolated showing preliminary cellulose degrading activity as deduced from halo formation around the bacterial colony when treated with Congo red (Figure 1A), eighty from glucose plates (1.2 × 108 colony forming units.ml-1) and thirty eight from the two lignocellulose substrate plates (2.0 × 105 colony forming units.ml-1).Figure 1

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