Optimization of Cellulase Production Conditions in Bacteria Isolated from Soils in Brazzaville

Objective: The objective of the present study is to optimize cellulase production in five strains: (Pantoea dispersa MLTBY6 (MT646430.1);Pseudomonas aeruginosa MLTBM2 (MT646431.1);Pseudomonas monteilii MLTBC10 (MT674682.1);Bacillus subtilis MLTBC5 (MT674681.1) and Lysinibacillus fusiformis MLTBB7 selected cellulase producers isolated from soils in Brazzaville, Republic of the Congo. Materials and Methods: The cellulolytic activity of the selected cellulase-producing strains was determined by transferring the strains to a petri dish containing CMC culture medium with the following composition: cellulose 1%, K2HPO4 0.2%, MgSO4 0.03%, peptone 1%, (NH4)2SO4 0.2% adjusted to a pH value of 7, previously poured and then frozen. The dishes were incubated in an oven at 37°C for 48 hours. The petri dishes were then flooded with 1% lugol for 15 minutes. A positive reading is indicated by the formation of a hydrolysis zone, the diameters of the hydrolysis zone were measured with a ruler. Strains with a broad lysis spectrum were selected. Optimisation of cellulase production by five bacterial strains isolated from the soil was done using the following factors: temperature and pH. Results: The production of cellulase showed that these strains showed a high production of cellulase at pH values between 5.6 and 9 with an optimum of pH = 8 and temperature values between 35°C and 40°C with an optimum at temperature t = 40°C. Of the carbon sources used, two sources, namely glucose and galactose, showed a high production of cellulase compared to the other carbon sources. However, the two nitrogen sources, ammonium sulphate and urea, were favourable for cellulase production by all five strains. Fe2+, CO2+, Zn2+ ions are favourable for cellulase production by these strains, with a referendum for Fe2+. Conclusion: From these results, we conclude that the sources of carbon (glucose and galactose), nitrogen (ammonium sulphate and urea) and ions (Fe2+, CO2+, Zn2+) added to these five strains were the elements favouring the good production of cellulase.