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Effect of Nutrients and Cellobiose Octaacetate on Cellulolytic Enzyme Productions by Streptomyces Albolongus

Sanjit Kumar Das
Department of Microbiology, University of Chittagong, Chittagong 4331, Bangladesh

M Zobaidul Alam
Department of Microbiology, University of Chittagong, Chittagong 4331, Bangladesh

M Abul Manchur
Department of Microbiology, University of Chittagong, Chittagong 4331, Bangladesh

M Nural Anwar
Department of Microbiology, University of Chittagong, Chittagong 4331, Bangladesh

Abstract/ Executive Summary:

The cellulolytic mesophilic isolate Streptomyces albolongus (A5) was used to determine the effect of nitrogen and carbon sources on the production of cellulolytic enzymes using cellobiose octaacetate (COA) as an inducer. The isolate was able to degrade various cellulosic carbon sources. However, the rate of degradation, production of extracellular protein, reducing sugar, saccharification and production of enzyme were enhanced when 0.6% COA was used as an inducer in addition to the main substrate. Among the nitrogen sources tested, beef extract showed maximum production of the enzyme (136.7 U/ml CMCase) in Winstead’s medium. The enzyme production was further enhanced in the medium supplemented with 0.6% COA, which corresponded to 154.69 U/ml CMCase activity. Among the carbon sources, carboxymethylcellulose (CMC) was found to be the best carbon source and again supplementation of the medium with 0.6% COA enhances CMCase production. Other than CMCase activity, the organism also produced appreciable levels of filter paper cellulase (FPase), avicelase and â-glucosidase activities.

Keywords: Streptomyces albolongus, Carboxymethylcellulose (CMC), Cellobiose octaacetate (COA), Induction

Location: Department of Microbiology, University of Chittagong, Chittagong

Start Date:

End Date:

Program Area: Resource Development and Management

Commodity: Fermenters

Objectives:

To investigate cellulose production by an actinomycete isolate, Streptomyces albolongus A5,using cellobiose octaacetate (COA) as an inducer for cellulose biosynthesis.

Methodology:

Streptomyces albolongus A5 was isolated from saw dust on selective cellulolytic medium and identified using standard procedure. Unless otherwise stated, cellulase production was carried out in shake-flask cultures in Winstead’s medium with an initial pH 6.5 containing 1.2% carboxymethylcellulose (CMC) with or without supplementation of 0.6% cellobiose octaacetate (COA) at 35°C for 5 days. After incubation, the culture filtrates were centrifuged to remove cells and other solids and the clear culture supernatants were used for enzyme assay and other analyses. Reducing sugar in the culture filtrates and the enzyme assay mixtures was estimated by using Nelson’s modification of Somogyi method16 using glucose as standard. Soluble protein in culture filtrates was estimated. The absorbance was read at 650 nm. Culture filtrates obtained by growing the organism on CMC medium was used for estimation of the degree of saccharification (%) using the following equation: Degree of saccharification (%) = Reducing sugar (mg/ml) / Substrate concentration (mg/ml) x 100. Carbooxymethylcellulase (CMCase) activity was determined by mixing 2 ml of culture supernatant to 2 ml substrate (1%CMC in phosphate buffer, pH 6.5), 1 ml of phosphate buffer and incubating the reaction mixture at 35°C for 2 h. Filter paper cellulase (FPase) was measured by incubating 2 ml of culture supernatant in 1 ml of phosphate buffer (pH 6.5) containing 50 mg Whatman No. 1 filter paper strip (1 x 6 cm) in a test tube. The reaction mixture was incubated at 35°C for 2 h. For determination of avicelase and β-glucosidase activities, 1% avicel and 1% salicin in phosphate buffer (pH 6.5) respectively were used as substrates. The amount of reducing sugars released, as glucose equivalents, in the enzyme reactions for CMCase, FPase, avicelase, or β-glucosidase assay was measured by Nelson-Somogyi method. Enzyme activity was expressed in terms of the amount of glucose released in mg/ml by the action of the crude enzyme on the respective substrates per hour.

Source of Information: Bangladesh J Microbiol, Volume 24, Number 1, June 2007, pp 70-72

Article Link (Online Journal):

Funding Source:

Budget:

Total Budget (Tk.) :

Achievement/Findings:

It was observed that, regardless of the substrate used, the enzyme production was enhanced to some extent in the presence of the inducer COA.

Knowledge Management: Journal