LOW ENERGY BACTERIA PRESERVATION OF EXTREMELY HALOPHILIC ARCHAEA HALOFERAX LUCENTENSE AND HALOFERAX CHUDINOVII IMMOBILIZED USING NATURAL ZEOLITE

Abstract

The methods of microbial cells preservation were already known by liquid drying, freeze-drying, and freezing. Those methods could preserve bacteria cells in a long period of time but its survivability was relatively low and used relatively high energy during preservation. Immobilization was known as entrapping, attaching or encapsulating bacterial cells in a suitable matrix. This research was conducted to know the suitability of zeolite as immobilization carrier and also as preservation matrix of two halophilic archaea Haloferax chudinovii and Haloferax lucentense. Variable of this research was the type of the carrier which was raw zeolite, 110oC and 300oC heat-activated zeolite carrier, parameters measured in this study was physical and chemical of zeolite such as chemical content, Si/Al ratio, surface area and pore volume, and biochemical assay, bacterial cells numbers after immobilization and bacterial cells after preservation as bacterial response to the immobilization and preservation. Heat activation was significantly affecting the chemical composition, carrier surface area, and pore volume. Highest surface area, pore volume, and Si/Al ratio were obtained in 110oC pretreated zeolite followed by 300oC pretreated zeolite. The bacterial cells obtained after immobilization process was 1,8x107 cfu/g, 3,0 x 107 cfu/g, and 2,1x107 for raw zeolite, 110oC pretreated zeolite and 300oC zeolite respectively. After 4 months preservation, the slight reduction of the bacterial cells was observed. Immobilization halophilic archaeae using zeolite as carrier was proven as low cost and effective preservation method due to relatively simple process and unspecific preservation temperature requirements.