Thermo-alkali-stable catalases from newly isolated Bacillus sp for the treatment and recycling of textile bleaching effluents

Three thermoalkaliphilic bacteria, which were grown at pH 9.3-10 and 60-65 degreesC were isolated out of a textile wastewater drain. The unknown micro -organisms were identified as thermoalkaliphilic Bacillus sp. Growth condit ions were studied and catalase activities and stabilities compared. Catalas es from Bacillus SF showed high stabilities at 60 degreesC and pH 9 (t(1/2) = 38 h) and thus this strain was chosen for further investigations, such a s electron microscopy, immobilization of catalase and hydrogen peroxide deg radation studies. Degradation of hydrogen peroxide with an immobilized cata lase from Bacillus SF enabled the reuse of the water for the dyeing process . In contrast, application of the free enzyme for treatment of bleaching ef fluents, caused interaction between the denaturated protein and the dye, re sulting in reduced dye uptake, and a higher color difference of 1.3 DeltaE* of dyed fabrics compared to 0.9 DeltaE* when using the immobilized enzyme. (C) 2001 Elsevier Science BN. All rights reserved.