Cultural Conditions Necessary for Optimal Cellulase Yield by Cellulolytic Bacterial Organisms as They Relate to Residual Sugars Released in Broth Medium

Abstract

A total of 115 samples made up of 42 (36.5%) rumen fluid, 36 (31.3%) cowdung and 37 (32.2%) soil samples were collected with the aid of sterile swab sticks except for rumen fluid samples which were collected by use of stomach tubes inserted into mouths of cows and by suction, liquor was collected into prewarmed thermo flasks under continuous flushing with carbondioxide. Soil samples were collected into sterile universal containers. All samples were obtained from abattoirs situated at three locations in Benin City, Nigeria. Samples were investigated for cellulolytic bacteria by Filter Paper Yeast Mineral broth method. Cellulase production was assayed by Carboxymethyl cellulose submerged broth culture while residual sugar yield and other cellulolytic activities were determined by 3, 5 -Dinitrosalicylic acid, Filter Paper, Microcrystalline and Viscometric methods. Cellullolytic bacterial organisms isolated from both soil and rumen fluids were Bacillus subtilis, Clostridium cellobioparum and Clostridium thermocellum. Pseudomonas aeruginosa was isolated from both soil and cowdung samples while Erwinia spp was obtained from both rumen fluid and cowdung samples. Bacillus circulans and Serratia spp were obtained from soil samples only. Clostridium thermocellum and Erwinia spp produced the highest and lowest cellulase yields respectively. All isolates at 40 o C and pH 6, recorded optimal sugar yields in culture broth of which Clostridium thermocellum recorded the highest. Lowest yields were recorded at 30 o C and pH 3 although there was significant difference in individual yields (P < 0.05). Clostridium thermocellum recorded optimal cellulolytic activities at 50 o C and pH 6. All isolates attained optimal cellulolytic activities at 32.6 ± 6.2 o C and pH 6.29 ± 0.9 with other broth cultural conditions kept constant. Implications of these findings are discussed.

Production and Characterization of Highly Thermostableβ-Glucosidase during the Biodegradation of Methyl Cellulose byFusarium oxysporum

“…The optimum pH recorded at pH 6.0 in this study supports the findings of Salahuddin et al and Pérez-Avalos et al, who obtained maximum production of β -glucosidase from mesophilic strains of actinomycete and Cellulomonas flavigena , respectively, at pH 6.0 [25, 26]. In the same way, Otajevwo and Aluyi reported maximum degradation of cellulose by Bacillus circulans at pH 6.0 [27]. However, Fawzi [28] reported optimum production of β -glucosidase Fusarium proliferatum NRRL26517 at pH 5.0 while Bansal et al [29] reported pH 7.0 as the optimum which supported maximum production of cellulases by A. niger NS-2.…”

Statistical optimization of lignocellulosic waste containing culture medium for enhanced production of cellulase by Bacillus tequilensis G9

“…The longer incubations make the bacterium capable of taking up maximum nutrients required for necessary cellular, metabolic or physiological changes prior to each binary fission. The enhancement in cellulase production by B. tequilensis G9 from basal level (OVAT approach) of 21.98 IU/ml extract to optimized 32.65 IU/ml extract in PB design followed by 44.02 IU/ml extract under RSM analysis was much higher than that of the optimal cellulase activities of Bacillus circulans (4.80 IU/ml), Bacillus subtilis (4.64 IU/ml), Clostridium thermocellum (5.32 IU/ml), at pH 6 after incubation at 40 °C [24]. Our results of cellulase activity were also higher than the activities observed by many authors [25][26][27] using PB design and RSM for optimization of cellulase production with Cellulomonas flavigena after 48 h. The probable reason for this higher activity could be variation in culture conditions and media used by the researchers previously.…”

Biology Education and Research in a Changing Planet

“…Hatami et al ( 2008 ) isolated aerobic cellulolytic bacteria from forest and farming soils and determined their ability to decompose cellulose. In another study, Otajevwo and Aluyi ( 2010 ) isolated Pseudomonas sp. YJ5 from soil samples, and cellulase activity was determined after 48 h of incubation.…”