Abstract

Eighty seven bacterial isolates were obtained from evaporator ponds using culture enrichment technique and screened for xylanase, mannanase and cellulase activity. Based on biochemical and phenotypic characteristics, the isolates were divided into 18 groups. Thirteen groups were Bacillus species, four were Halomonas species, while one group belonged to the genus Nesterenkonia. Four Bacillus isolates, Sua-BAC005, Sua-BAC012, Sua-BAC017 and Sua-BAC019, as well as Nesterenkoniasp. Sua-BAC020 were studied further. Isolate Sua-BAC005 affiliated with Bacillus amyloliquefaciens secreted 12.6 U/ml and 9.0 U/ml b-mannanase and b-xylanase, respectively, while isolates Sua-BAC012, Sua-BAC017 and Sua-BAC019 affiliated with Bacillus licheniformis, produced less than 2 U/ml of xylanase, cellulase and mannanase. Nesterenkonia sp. Sua-BAC020 grew at 0 – 20% NaCl with an optimum at 2.5% NaCl, and at pH 7 – 9.5 with an optimum at pH 9. This isolate produced 3.5 U/ml xylanase when cultivated at pH 8 in 10% NaCl. Five xylanase activity bands were detected on Native-PAGE coupled with zymogram.

Key words: Halomonas, xylanase, halophiles, alkaliphiles, xylanase multiplicity.