The characteristics of a new non‐spore‐forming cellulolytic mesophilic anaerobe strain CM126 isolated from municipal sewage sludge

Abstract

A new mesophilic anaerobic cellulolytic bacterium, CM126, was isolated from an anaerobic sewage sludge digester. The organism was non-spore-forming, rod-shaped, Gram-negative and motile with peritrichous flagella. It fermented microcrystalline Avicel cellulose, xylan, Solka floc cellulose, filter paper, L-arabinose, D-xylose, beta-methyl xyloside, D-glucose, cellobiose and xylitol and produced indole. The % G + C content was 36. Acetic acid, ethanol, lactic acid, pyruvic acid, carbon dioxide and hydrogen were produced as metabolic products. This strain could grow at 20-44.5 degrees C and at pH values 5.2-7.4 with optimal growth at 37-41.5 degrees C and pH 7. Both endoglucanase and xylanase were detected in the supernatant fluid of a culture grown on medium containing Avicel cellulose and cellobiose. Exoglucanase could not be found in either supernatant fluid or the cell lysate. When cellulose and cellobiose fermentation were compared, the enzyme production rate in cellobiose fermentation was higher than in cellulose fermentation. The optimum pH for both enzyme activities was 5.0, the optimum temperature was 40 degrees C for the endoglucanase and 50 degrees C for the xylanase. Both enzyme activities were inhibited at 70 degrees C Co-culture of this organism with a Methanosarcina sp. (A145) had no effect on cellulose degradation and both endoglucanase and xylanase were stable in the co-culture.

Reduction of Soybean Meal Non-Starch Polysaccharides and α-Galactosides by Solid-State Fermentation Using Cellulolytic Bacteria Obtained from Different Environments

“…The total cellulase activity was assessed using a modification of the filter paper method and an incubation period of 24 h at 50°C [29]. One unit of total cellulase activity was defined as the amount in µmoles of glucose released per minute per one ml of cultured bacterial supernatant [30]. The endo-β-xylanase and α-D-galactosidase activities were assessed using the p-nitrophenyl derivatives method; one unit of β-xylanase and α -galactosidase activity was defined as the µmoles of p-nitrophenol released per minute per millilitre of cultured bacterial supernatant at 25°C [31].…”

Enrichment and Identification of Cellulolytic Bacteria from the Gastrointestinal Tract of Giant African Snail, Achatina fulica

“…Endoglucanase (CMCase) and exoglucanase (avicelase) activities were determined according to the method described by Nitisinprasert and Temmes [18]. The estimation of proteins was carried out by Bradford method [19] using BSA as standard.…”

Multicomponent cellulase production by Cellulomonas biazotea NCIM‐2550 and its applications for cellulosic biohydrogen production

“…Exoglucanase (avicelase) activity was also performed by using the method of Nitisinprasert and Temmes. 19 In this assay method, the reaction mixture containing 2 mL enzyme solution with 1 mL of 1% avicel cellulose in McIlvaine's buffer (pH 5) was incubated at 40 C for 2 h. The reaction was terminated by filtration through a 0.45-lm membrane filter (Millipore) and addition of 2 mL of dinitrosalicylic acid reagent. In these tests, reducing sugars were estimated colorimetrically with dinitrosalicylic reagent method, using glucose as standard.…”