Cellulase production by thermophilic Bacillus sp: SMIA-2 and its detergent compatibility

Background This paper reports the production of cellulase by thermophilic Bacillus sp. SMIA-2 using sugarcane bagasse and corn steep liquor as substrates. Some biochemical properties of the enzyme were also assessed for the purposes of exploiting its potential in the detergent industry, as well as other suitable applications. Results Bacillus sp. produced cellulases when cultivated at 50°C in liquid cultures containing sugarcane bagasse and corn steep liquor. Maximum avicelase (0.83 U mL-1) and CMCase (0.29 U mL-1) activities were reached in 120 h and 168 h of culturing time, respectively. The avicelase and CMCase presented an optimum activity at pH of 7.5 and 8.0, respectively. The maximum stability of avicelase and CMCase was observed at a pH range between 6.5-8.0 and 7.0-9.0 respectively, where they retained more than 70% of their maximum activities after incubation at room temperature for 3 h. The optimum temperature of avicelase and CMCase was 70°C, and both enzymes remained 100% stable until the treatment at 60°C for 1 h. Bacillus sp. cultures also released proteases into the culture medium, but the cellulases were resistant to protease digestion. The compatibility of cellulases varied with each laundry detergent tested, being more stable in the presence of Ultra Biz® and less with Ariel®. In addition, the enzyme was stable in sodium dodecyl sulfate and RENEX-95, and was inhibited by TritonX-100 and H2O2. Conclusions The properties presented by Bacillus sp. SMIA-2 suggest that this organism might become a potential source of lignocellulose-degrading enzymes for industrial applications such as in the detergent industry.

Optimization and characterization of alkaline protease and carboxymethyl-cellulase produced by Bacillus pumillus grown on Ficus nitida wastes

The potentiality of 23 bacterial isolates to produce alkaline protease and carboxymethyl-cellulase (CMCase) on Ficus nitida wastes was investigated. Bacillus pumillus ATCC7061 was selected as the most potent bacterial strain for the production of both enzymes. It was found that the optimum production of protease and CMCase were recorded at 30 °C, 5% Ficus nitida leaves and incubation period of 72 h. The best nitrogen sources for protease and CMCase production were yeast extract and casein, respectively. Also maximum protease and CMCase production were reported at pH 9 and pH 10, respectively. The enzymes possessed a good stability over a pH range of 8-10, expressed their maximum activities at pH10 and temperature range of 30-50 °C, expressed their maximum activities at 50 °C. Ions of Hg2+, Fe2+ and Ag+ showed a stimulatory effect on protease activity and ions of Fe2+, Mg2+, Ca2+, Cu2+ and Ag+ caused enhancement of CMCase activity. The enzymes were stable not only towards the nonionic surfactants like Triton X-100 and Tween 80 but also the strong anionic surfactant, SDS. Moreover, the enzymes were not significantly inhibited by EDTA or cystein. Concerning biotechnological applications, the enzymes retained (51-97%) of their initial activities upon incubation in the presence of commercials detergents for 1 h. The potential use of the produced enzymes in the degradation of human hair and cotton fabric samples were also assessed.

Multivariable parameter optimization for the endoglucanase production by Trichoderma reesei Rut C30 from Ocimum gratissimum seed

The aim of this study was to evaluate the interaction effects of the physico-chemical parameters on the endoglucanase (CMCase) production by Trichoderma reesei Rut C30 on a cellulosic agro-residue by the solid-state fermentation (SSF) and to determine their optimum values by the EVOP factorial design technique. The best combination of physical parameters for the maximum production of the endoglucanase (CMCase) was 28ºC temperature, 79 percent relative humidity and 4.8 pH of the medium. The best combination of the chemical parameters was (mg/L) nicotinic acid 15, naphthalene acetic acid 7, ferric chloride 5 and Tween-80 6. With the application of this technique, the yield of the CMCase increased by ~ 2.3 fold.