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Isolation and identification of local Bacillus isolates for xylanase biosynthesis.

Ammoneh H, Harba M, Akeed Y, Al-Halabi M, Bakri Y - Iran J Microbiol (2014)

Bottom Line: 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.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.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Biology and Biotechnology, AECS, Damascus, Syria.

ABSTRACT

Background and objectives: 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.

Materials and 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.

No MeSH data available.


Effect of pH on the xylanase stability of three Bacillus strains.
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Figure 5: Effect of pH on the xylanase stability of three Bacillus strains.

Mentions: Up to date, xylanases produced by most alkaliphiles are reported to have their optimum pH around neutrality. Nakamura et al. (17) reported the first alkaline xylanases produced by Bacillus sp. strain 41 M-1, which had an optimum pH at 9.0. Yang et al. (28) isolated an alkaliphilic Bacillus sp. VI-4 from a hard wood kraft pulp, which produced xylanase having an optimum pH of 6-8.5. Similarly, the optimum pH activity at 6.8-7.0 of xylanase reported from B. amyloliquefaciens (11). Thermostable alkaline xylanase from a Bacillus sp. showed three optimum peaks for pH 6.5, 8.5 and 10.5 (23). A wide range of pH activity from 5.0-8.0 was observed in B. circulans BL53 upon solid state cultivation (12). The activity persistence in a large range of pH is a desirable quality of an industrial enzyme. When pH stability was measured at values between 4 and 10, the xylanase stability was over a broad neutral to alkaline pH range (6-10) and retained more than 75% of its activity after 24 h of incubation at room temperature (Fig. 5). Stability at extreme pH values may be due to charged amino acid residues. The enzymes stable in alkaline conditions were characterized by a decreased number of acidic residues and an increased number of arginines (8).


Isolation and identification of local Bacillus isolates for xylanase biosynthesis.

Ammoneh H, Harba M, Akeed Y, Al-Halabi M, Bakri Y - Iran J Microbiol (2014)

Effect of pH on the xylanase stability of three Bacillus strains.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4281660&req=5

Figure 5: Effect of pH on the xylanase stability of three Bacillus strains.
Mentions: Up to date, xylanases produced by most alkaliphiles are reported to have their optimum pH around neutrality. Nakamura et al. (17) reported the first alkaline xylanases produced by Bacillus sp. strain 41 M-1, which had an optimum pH at 9.0. Yang et al. (28) isolated an alkaliphilic Bacillus sp. VI-4 from a hard wood kraft pulp, which produced xylanase having an optimum pH of 6-8.5. Similarly, the optimum pH activity at 6.8-7.0 of xylanase reported from B. amyloliquefaciens (11). Thermostable alkaline xylanase from a Bacillus sp. showed three optimum peaks for pH 6.5, 8.5 and 10.5 (23). A wide range of pH activity from 5.0-8.0 was observed in B. circulans BL53 upon solid state cultivation (12). The activity persistence in a large range of pH is a desirable quality of an industrial enzyme. When pH stability was measured at values between 4 and 10, the xylanase stability was over a broad neutral to alkaline pH range (6-10) and retained more than 75% of its activity after 24 h of incubation at room temperature (Fig. 5). Stability at extreme pH values may be due to charged amino acid residues. The enzymes stable in alkaline conditions were characterized by a decreased number of acidic residues and an increased number of arginines (8).

Bottom Line: 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.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.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Biology and Biotechnology, AECS, Damascus, Syria.

ABSTRACT

Background and objectives: 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.

Materials and 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.

No MeSH data available.