PRODUCTION AND PHYSICOCHEMICAL PROPERTIES OF THERMOSTABLE, CRUDE CELLULASE FROM ENTEROBACTER CLOACAE IP8 ISOLATED FROM PLANT LEAF LITTERS OF LAGERSTROEMIA INDICA Linn.

Abstract

Cellulases have wide applications and biotechnological potentials for various industries. A bacterium producing an extracellular, thermostable cellulase was isolated from plant leaf litters of Lagerstroemia indica Linn, inside a botanical garden. According to morphological, biochemical and physiological characterization, it was tentatively identified as Enterobacter sp. Molecular characterization, using the 16S rRNA gene sequencing was used to confirm the identity of the bacterium as Enterobacter cloacae IP8. Effects of some cultural factors such as carbon and nitrogen sources, pH and temperature, on cellulase production from the bacterium, were investigated. Some physicochemical properties of the crude cellulase from E. cloacae IP8 were determined to evaluate its potentials for industrial applications. The maximum yield of cellulase (10.78 U/mL) was at 28 h of incubation using carboxymethyl cellulose (CMC) (1.5%, w/v), peptone (2.0%, w/v), inoculum size (1.0%, v/v), pH and temperature of 7.0 and 45 oC, respectively, and agitation speed 150 rpm. The crude cellulase exhibited optimum activity at 60 oC, retaining 75.0% of its maximal activity at 70 oC. It had optimum pH of 7.0, retaining 58.0% of its original activity at acidic pH 5.0. Metal ions Na+, Ca2+ and Mg2+ remarkably enhanced activity of the cellulase while K+ and EDTA inhibited activity of the cellulase from E. cloacae IP8. The characteristics of the cellulase from E. cloacae IP8 revealed the enzyme as being thermostable and an acidic to neutral metalloenzyme. Therefore, the enzyme from this strain could be applied in industrial applications such as lignocellulosic biomass conversion into fuel and other value added products.

Cloning of cellulase gene using metagenomic approach of soils collected from Wadi El Natrun, an extremophilic desert valley in Egypt

“…Fe 2+ , Mn 2 , and Cu 2+ caused a decrease in the cellSNSY enzyme activity. These results agreed with the results obtained by many researchers [ 57 – 59 ], who reported that both Ca 2+ and Na + cations exhibited stimulatory effects on the enzyme activity in all tested concentrations. The results of the under investigation are in agreement with Asha et al [ 40 ] who reported for the activity of the purified cellulase from Paenibacillus barcinonensis which is stimulated in the presence of metal ions such as Mg 2+ , Mn 2+ , and Co 2+ .…”

“…Also, Chai et al [ 22 ] found that the cellulase activity was increased by Mn 2+ , Ca 2+ , Zn 2+ , and Mg 2+ at 1 mM. In contrast to ones’ results, Akintola et al [ 57 ] reported that Mg +2 inhibited the activity of cellulase from Enterobacter cloacae IP8 at concentration 4 mM to 15 mM; it stimulated its activity at concentrations (ranged 20–200 mM). Gong et al [ 49 ] noticed that the recombinant Cel14b22 was considerably enhanced by Mn 2+ , but intensely reduced by Fe 3+ or Cu 2+…”

“…By testing EDTA (1 mM), the studied recombinant cellSNSY lost 5% of its activity, while Akintola et al [ 57 ] reported that EDTA at concentrations above 4 mM inhibited the activity of the crude cellulase from the bacterium ( Enterobacter cloacae IP8). Similarly, EDTA caused the inhibition of cellulase which was produced by Acetobacter xylinum Ku-1 [ 60 ].…”

Peanut Endophytic Phosphate Solubilizing Bacteria Increase Growth and P Content of Soybean and Maize Plants

“…These results coincide with those reported for S. marcescens strain where cellulase production acts as primary metabolite, since it occurs from cell growth stage to the end of exponential stage or beginning of stationary stage [50]. Regarding bacteria of genus Enterobacter, the bibliography indicates that this relationship is strain dependent [51,52].…”

Isolation and Identification of Bacteria of Genus Bacillus from Composting Urban Solid Waste and Palm Forest in Northern Peru

“…Cellulose chemically consists of several β-glucose subunits linked by β-1,4-glucosidic bonds. Cellulases break the bonds of this molecule [ 8 , 9 ]. The intermolecular bonds of cellulose create a particularly very tough crystalline molecule; therefore, the cellulolytic activity requires multiple complex enzyme systems for enzymatic hydrolysis, requiring the synergistic action of endo-glucanase, exo-glucanase, and glucosidase enzymes that degrade cellulose converting the products into a usable energy source [ 1 ].…”