title: Isolation and identification of local Bacillus isolates for xylanase biosynthesis.
abstract: OBJECTIVE
  Bacillus species are attractive industrial organisms due to their rapid growth rates leading to a short fermentation cycle and for their capacity to secrete important enzymes and proteins such as xylanase into the extracellular medium. Considering the industrial importance of xylanase, in this current study, Bacillus spp. were isolated from different soils and were screened for their xylanase production.
  
  
  METHODS
  Bacillus isolates used in this study were obtained from a national screening program carried out during 2006-2007 in which soil samples that covered areas throughout the interior of Syria were collected. The prepared inoculum from each of Bacillus isolates was aliquoted onto xylan agar plates, incubated at 30°C for 72 h and screened for xylanase synthesis.
  
  
  RESULTS
  Xylanolytic isolates were selected depending on the clear zones of xylan hydrolysis. Fifteen isolates having the highest clearing zone were determined and grown in a solid state fermentation. Of the 15 isolates, three bacilli namely SY30A, SY185C and SY190E that showed maximum xylanase production, were identified using the 16S rDNA sequencing method. According to 16S rDNA gene sequence data, the closest phylogenetic neighbor for SY30A was Bacillus pumilus and for SY185C and SY190E isolates was Bacillus subtilis. Optimal pH and temperature for xylanase activity was 7.0 and 55ºC for SY30A and 6.0 and 60ºC for SY185C and SY190E, respectively. Under these conditions, the following activities were found to be around 1157 ± 58, 916 ± 46 and 794 ± 39 (U/g) for SY30A, SY185C and SY190E, respectivly.
  
  
  CONCLUSIONS
  Selected local Bacillus isolates were found to be a potential source of xylanase which was proven to be quite suitable for multiple biotechnological applications. These isolates might after extensive optimization steps be an alternative to commercially available strains.
authors.affiliation: Department of Molecular Biology and Biotechnology, AECS, Damascus, Syria.
authors.forename: Hassan
authors.initials: H
authors.lastname: Ammoneh
authors.affiliation: Department of Molecular Biology and Biotechnology, AECS, Damascus, Syria.
authors.forename: Muhanad
authors.initials: M
authors.lastname: Harba
authors.affiliation: Department of Molecular Biology and Biotechnology, AECS, Damascus, Syria.
authors.forename: Yasser
authors.initials: Y
authors.lastname: Akeed
authors.affiliation: Department of Molecular Biology and Biotechnology, AECS, Damascus, Syria.
authors.forename: Mohanad
authors.initials: M
authors.lastname: Al-Halabi
authors.affiliation: Department of Molecular Biology and Biotechnology, AECS, Damascus, Syria.
authors.forename: Yasser
authors.initials: Y
authors.lastname: Bakri
keywords: Bacillus sp; Solid state culture; Xylanase