| Literature DB >> 25691925 |
Shokoofeh Ghazi1, Abbas Akhavan Sepahy2, Mehrdad Azin3, Khosro Khaje4, Ramazanali Khavarinejad1.
Abstract
OBJECTIVES: This study highlights xylanase overproduction from Bacillus mojavensis via UV mutagenesis and optimization of the production process.Entities:
Keywords: Bacillus mojavensis; H/C ratio; Optimization; Random mutagenesis; Xylanase
Year: 2014 PMID: 25691925 PMCID: PMC4328092
Source DB: PubMed Journal: Iran J Basic Med Sci ISSN: 2008-3866 Impact factor: 2.699
Design table for the first phase of optimization (Factors and their levels)
| Multilevel factorial design | |||
|---|---|---|---|
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| |||
| Factors | 3 | Replicates: | 2 |
| Base runs | 60 | Total runs | 120 |
| Base blocks | 1 | Total blocks | 2 |
| Number of levels | 5, 4, 3 | ||
| Factor | Type | Levels | Values |
| Carbon source | Fixed | 5 | Wheat bran, Oat bran, Rice bran, Molasses, Bagasse |
| Nitrogen source | Fixed | 4 | Corn steep Liquor powder, Fish protein, Soy protein, Natural bakery yeast powder |
| Time course production profile | Fixed | 3 | 24 hr, 48 hr, 72 hr |
Central composite experimental design chart at 3rd phase of optimization
| Central composite design (CCD) | |
|---|---|
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| |
| Factors:5 | Replicates: 2 |
| Base runs: 32 | Total runs:64 |
| Base blocks: 1 | Total blocks:1 |
| Two-level factorial: Half fraction | |
| Cube points: | 32 |
| Center points in cube: | 12 |
| Axial points: 20 | |
| Center points in axial: 0 | |
Full factorial design for determination of optimum pH and temperature of enzyme activity. Variables and their levels
| Multilevel factorial design | |||
|---|---|---|---|
|
| |||
| Factors: 2 | Replicates: 2 | ||
| Base runs: 30 | Total runs: 60 | ||
| Base blocks: 1 | Total blocks: 1 | ||
| Number of levels: 5, 6 | |||
| General linear model: Enzyme activity (IU/ml) versus pH, Temperature | |||
| Factor | Type | Levels | Values |
| pH | Fixed | 5 | 7, 8, 9, 10, 11 |
| Temperature | Fixed | 6 | 30, 40, 50, 60, 70, 80 (°C) |
Figure 1.The effect of UV light irradiation on survival of Bacillus mojavensis PTCC1723. Data points have been expressed as means= 2)
Figure 2.Results for first and secondary screening step: A: Comparison of H/C ratio among mutant colonies treated with UV rays B: Frequency of mutants with bigger H/C ration than that of the parental strain C: Comparison of enzyme production level among mutant strains D: Frequency of mutants with higher enzyme production level than that of the parental strain. Data points have been expressed as means (n=3)
Figure 3.Main effects of 3 chief factors on enzyme production at first phase of optimization
Figure 4.Significant factors that affect high xylanase production in liquid culture
Figure 5.Contour plots of xylanase production from mutant number 17, and interactions between variables two by two: A: Interaction of corn steep liquor and wheat barn. B: Interaction of rpm and natural bakery yeast powder. C: Interaction of rpm and wheat barn. D: Interaction of K2HPO4 and wheat barn. E: Interaction of natural bakery yeast powder and corn steep liquor. F: Interaction of K2HPO4 and corn steep liquor. G: Interaction of rpm and K2HPO4. H: Interaction of natural bakery yeast powder and K2HPO4. I: Interaction of natural bakery yeast powder and wheat barn. J: Interaction of rpm and corn steep liquor
Verification test chart designed with Minitab software
| Response optimization | ||||||
|---|---|---|---|---|---|---|
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| Actual response: Xylanase activity = 575 IU/ml | ||||||
| Parameters | ||||||
| Goal | Lower | Target | Upper | Weight | Import | |
| Enzyme activity | Maximum | 430 | 580 | 580 | 1 | 1 |
| Global solution | ||||||
| Wheat bran= 7.5 | ||||||
| Corn steep liquor powder= 6 | ||||||
| K2HPO4 (g/l)= 0.5 | ||||||
| Natural bakery yeast powder= 12.5 | ||||||
| rpm= 230 | ||||||
| Predicted responses | ||||||
| Enzyme activity= 600.144 , desirability = 1.000000 | ||||||
| Composite desirability= 1.000000 | ||||||
Figure 6.Xlanase characterization produced from mutant strain: A: Optimal pH and temperature of xylanase activity. B: pH and temperature profile of xylanase activity from mutant strain. C: pH stability pattern of xylanase from mutant strain. D: Thermal stability pattern of xylanase from mutant strain
Experimental range and levels of independent variables in second phase of optimization
| Wheat bran (g/ l) | Corn steep Powder(g/l) | Inoculum %( v/v) | K2HPO4(g/l) | KH2PO4 (g/L) | MgSO4.7H2O (g/ l | pH | Tem | Rpm | Malt extract (g/l) | Natural bakery yeast (g/l) | Tween 80 % (v/v) | Trace elements solution %(v/v) |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
| ||||||||||||
| 20.0 | 5.0 | 10 | 1.0 | 0.0 | 0.0 | 7 | 30.0 | 200 | 0.0 | 5.0 | 0.0 | 0.2 |
| 20.0 | 10.0 | 2 | 1.0 | 1.0 | 0.0 | 7 | 30.0 | 160 | 5.0 | 0.0 | 0.2 | 0.0 |
| 15.0 | 10.0 | 10 | 0.0 | 1.0 | 0.2 | 7 | 30.0 | 160 | 0.0 | 5.0 | 0.0 | 0.2 |
| 15.0 | 5.0 | 10 | 1.0 | 0.0 | 0.2 | 9 | 30.0 | 160 | 0.0 | 0.0 | 0.2 | 0.0 |
| 20.0 | 5.0 | 2 | 1.0 | 1.0 | 0.0 | 9 | 37.0 | 160 | 0.0 | 0.0 | 0.0 | 0.2 |
| 20.0 | 10.0 | 2 | 0.0 | 1.0 | 0.2 | 7 | 37.0 | 200 | 0.0 | 0.0 | 0.0 | 0.0 |
| 20.0 | 10.0 | 10 | 0.0 | 0.0 | 0.2 | 9 | 30.0 | 200 | 5.0 | 0.0 | 0.0 | 0.0 |
| 20.0 | 10.0 | 10 | 1.0 | 0.0 | 0.0 | 9 | 37.0 | 160 | 5.0 | 5.0 | 0.0 | 0.0 |
| 15.0 | 10.0 | 10 | 1.0 | 1.0 | 0.0 | 7 | 37.0 | 200 | 0.0 | 5.0 | 0.2 | 0.0 |
| 20.0 | 5.0 | 10 | 1.0 | 1.0 | 0.2 | 7 | 30.0 | 200 | 5.0 | 0.0 | 0.2 | 0.2 |
| 15.0 | 10.0 | 2 | 1.0 | 1.0 | 0.2 | 9 | 30.0 | 160 | 5.0 | 5.0 | 0.0 | 0.2 |
| 20.0 | 5.0 | 10 | 0.0 | 1.0 | 0.2 | 9 | 37.0 | 160 | 0.0 | 5.0 | 0.2 | 0.0 |
| 15.0 | 10.0 | 2 | 1.0 | 0.0 | 0.2 | 9 | 37.0 | 200 | 0.0 | 0.0 | 0.2 | 0.2 |
| 15.0 | 5.0 | 10 | 0.0 | 1.0 | 0.0 | 9 | 37.0 | 200 | 5.0 | 0.0 | 0.0 | 0.2 |
| 15.0 | 5.0 | 2 | 1.0 | 0.0 | 0.2 | 7 | 37.0 | 200 | 5.0 | 5.0 | 0.0 | 0.0 |
| 15.0 | 5.0 | 2 | 0.0 | 1.0 | 0.0 | 9 | 30.0 | 200 | 5.0 | 5.0 | 0.2 | 0.0 |
| 20.0 | 5.0 | 2 | 0.0 | 0.0 | 0.2 | 7 | 37.0 | 160 | 5.0 | 5.0 | 0.2 | 0.2 |
| 20.0 | 10.0 | 2 | 0.0 | 0.0 | 0.0 | 9 | 30.0 | 200 | 0.0 | 5.0 | 0.2 | 0.2 |
| 15.0 | 10.0 | 10 | 0.0 | 0.0 | 0.0 | 7 | 37.0 | 160 | 5.0 | 0.0 | 0.2 | 0.2 |
| 15.0 | 5.0 | 2 | 0.0 | 0.0 | 0.0 | 7 | 30.0 | 160 | 0.0 | 0.0 | 0.0 | 0.0 |
| 17.5 | 7.5 | 6 | 0.5 | 0.5 | 0.1 | 8 | 33.5 | 180 | 2.5 | 2.5 | 0.1 | 0.1 |
| 20.0 | 5.0 | 10 | 1.0 | 0.0 | 0.0 | 7 | 30.0 | 200 | 0.0 | 5.0 | 0.0 | 0.2 |
| 20.0 | 10.0 | 2 | 1.0 | 1.0 | 0.0 | 7 | 30.0 | 160 | 5.0 | 0.0 | 0.2 | 0.0 |
| 15.0 | 10.0 | 10 | 0.0 | 1.0 | 0.2 | 7 | 30.0 | 160 | 0.0 | 5.0 | 0.0 | 0.2 |
| 15.0 | 5.0 | 10 | 1.0 | 0.0 | 0.2 | 9 | 30.0 | 160 | 0.0 | 0.0 | 0.2 | 0.0 |
| 20.0 | 5.0 | 2 | 1.0 | 1.0 | 0.0 | 9 | 37.0 | 160 | 0.0 | 0.0 | 0.0 | 0.2 |
| 20.0 | 10.0 | 2 | 0.0 | 1.0 | 0.2 | 7 | 37.0 | 200 | 0.0 | 0.0 | 0.0 | 0.0 |
| 20.0 | 10.0 | 10 | 0.0 | 0.0 | 0.2 | 9 | 30.0 | 200 | 5.0 | 0.0 | 0.0 | 0.0 |
| 20.0 | 10.0 | 10 | 1.0 | 0.0 | 0.0 | 9 | 37.0 | 160 | 5.0 | 5.0 | 0.0 | 0.0 |
| 15.0 | 10.0 | 10 | 1.0 | 1.0 | 0.0 | 7 | 37.0 | 200 | 0.0 | 5.0 | 0.2 | 0.0 |
| 20.0 | 5.0 | 10 | 1.0 | 1.0 | 0.2 | 7 | 30.0 | 200 | 5.0 | 0.0 | 0.2 | 0.2 |
| 15.0 | 10.0 | 2 | 1.0 | 1.0 | 0.2 | 9 | 30.0 | 160 | 5.0 | 5.0 | 0.0 | 0.2 |
| 20.0 | 5.0 | 10 | 0.0 | 1.0 | 0.2 | 9 | 37.0 | 160 | 0.0 | 5.0 | 0.2 | 0.0 |
| 15.0 | 10.0 | 2 | 1.0 | 0.0 | 0.2 | 9 | 37.0 | 200 | 0.0 | 0.0 | 0.2 | 0.2 |
| 15.0 | 5.0 | 10 | 0.0 | 1.0 | 0.0 | 9 | 37.0 | 200 | 5.0 | 0.0 | 0.0 | 0.2 |
| 15.0 | 5.0 | 2 | 1.0 | 0.0 | 0.2 | 7 | 37.0 | 200 | 5.0 | 5.0 | 0.0 | 0.0 |
| 15.0 | 5.0 | 2 | 0.0 | 1.0 | 0.0 | 9 | 30.0 | 200 | 5.0 | 5.0 | 0.2 | 0.0 |
| 20.0 | 5.0 | 2 | 0.0 | 0.0 | 0.2 | 7 | 37.0 | 160 | 5.0 | 5.0 | 0.2 | 0.2 |
| 20.0 | 10.0 | 2 | 0.0 | 0.0 | 0.0 | 9 | 30.0 | 200 | 0.0 | 5.0 | 0.2 | 0.2 |
| 15.0 | 10.0 | 10 | 0.0 | 0.0 | 0.0 | 7 | 37.0 | 160 | 5.0 | 0.0 | 0.2 | 0.2 |
| 15.0 | 5.0 | 2 | 0.0 | 0.0 | 0.0 | 7 | 30.0 | 160 | 0.0 | 0.0 | 0.0 | 0.0 |
| 17.5 | 7.5 | 6 | 0.5 | 0.5 | 0.1 | 8 | 33.5 | 180 | 2.5 | 2.5 | 0.1 | 0.1 |