Hydrogen peroxide degradation by immobilized cells of alkaliphilic Bacillus halodurans
Abstract
Whole cells of Bacillus halodurans LBK 261 were used as a source of catalase for degradation of hydrogen peroxide. The organism, B. halodurans grown at 55°C and pH 10, yielded a maximum catalase activity of 275 U g−1 (wet wt.) cells. The catalase in the whole cells was active over a broad range of pH with a maximum at pH 8–9. The enzyme was optimally active at 55°C, but had low stability above 40°C. The whole cell biocatalyst exhibited a Km of 6.6 mM for H2O2 and Vmax of 707 mM H2O2 min−1 g−1 wet wt. cells, and showed saturation kinetics at 50 mM H2O2. The cells were entrapped in calcium alginate and used for H2O2 degradation at pH 9 in batch and continuous mode. In the batch process, the immobilized preparation containing 1.5 g (wet wt.) cells could be recycled at least four times for complete degradation of the peroxide in 50 mL solution at 25°C. An excess of immobilized biocatalyst could be used in a continuous stirred tank reactor for an average of 9 days at temperatures upto 55°C, and in a packed bed reactor (PBR) for 5 days before the beads started to deform.
URI
http://profiles.uonbi.ac.ke/mulaafj/publications/hydrogen-peroxide-degradation-immobilized-cells-alkaliphilic-bacillus-haloduranhttp://erepository.uonbi.ac.ke:8080/xmlui/handle/123456789/17581
Citation
Biocatalysis and Biotransformation, 24. 3,. 215-222, (2006)Publisher
Department of Biochemistry, University of Nairobi, Nairobi, Kenya Read More: http://informahealthcare.com/doi/abs/10.1080/10242420600662669
Collections
- Faculty of Health Sciences (FHS) [10378]