Decolourisation of amaranth azo dye by bacterial consortium immobilized ontozeolite nax and surfactant modified zeolite nax

Three bacterial strains Citrohacter freundii strain A1, Enterococcus casseliflavus strain Cl, and Enterobacter cloacae strain L17 in consortium onto zeolite NaX were studied for their ability to decolourise the azo dye, Amaranth. Zeolite NaX, an inorganic nanoporous material as well as surfactant modified zeolite NaX (SMZ) were used as the solid support matrix for bacterial immobilization. All optimised parameters for instance inoculum size, dye, temperature and amount of zeolite previously determ ined were applied using the both types o f bacteria immobilized nanoporous support. Complete decolourisation of Amaranth was achieved anaerobically within 20 minutes by inoculating 10% (v/v) bacterial consortium of Al, Cl. and L17 at a 1:1:1 ratio with SMZ NaX, while 30 minutes for decolourisation of Amaranth by zeolite NaX. This was achieved in a 1/4 strength P5 medium ( pH7) containing 5 g/L of nutrient broth supplement, 2.5 g/L of glucose, incubated at 45°C under anaerobic condition. Presence of bacterial consortium immobilized onto inorganic nanoporous material was determined via Scanning Electron Microscopy (SEM). SEM micrographs confirm that the adsorption of the bacteria on the surface of the SMZ was better than zeolite NaX thus enhances decolourisation process

Production of cyclodextrin glucanotransferase (CGTase) from alkalophilic Bacillus sp. TS1-1: Media optimization using experimental design

Cyclodextrin glucanotransferase (CGTase) was produced when the Bacillus sp. TS1-1 was grown in a medium containing sago starch, yeast extract, phosphorus and mineral salt sources, using shake flask mode at 37°C for 24 h. Response surface methodology (RSM) was applied to optimize the medium constituents with respect to CGTase production and activity. A 24 full factorial design (first order model) was carried out to identify the significant effect of medium components towards CGTase production. The variables involved in this initial screening study were sago starch, yeast extract, K2HPO 4 and MgSO4·7H2O. Statistical analysis of results have shown that only sago starch and yeast extract have a significant effect on CGTase production. A second-order model was proposed by using 2 2 central composite design to represent the production CGTase activity as a function of sago starch and yeast extract. The optimized values of 1.48% and 1.89% of sago starch and yeast extract was obtained, respectively. Under these proposed optimized conditions, the model predicted a CGTase activity of 79.66 U/ml and via experimental rechecking the model, an activity of 84 U/ml was attained

Hydrothermal conversion of rice husk ash to faujasite-types and NaA-type of zeolites

The faujasite-type of zeolites (NaX and NaY) and NaA-type of zeolite were synthesized from rice husk ash (RHA) via the hydrothermal conditions. The combustion of rice husk at controlled temperature of 600 °C for an hour in open air produce more than 90% of amorphous silica in the ash which was reactive towards the synthesis of zeolites. The formation of zeolite NaY from RHA is metastable and thus, the seeding and ageing effects in the synthesis of zeolite NaY were investigated to avoid the formation of zeolite A or P as the impurities in zeolite NaY. Zeolites NaX and NaA were also successfully synthesized with high purity, absence of impurities and other phases, and high reproducibility. Thus, the amorphous forms of silica in RHA can be used as a source of silica for the synthesis of faujasite-types and NaA-type of zeolites