Abstract
Physical and chemical mutagens are promising and are used for screening of high yielding strains. The exponential increase in the application of amylases in various fields has placed stress and demand in both qualitative improvement and quantitative enhancement through strain improvement. Ultraviolet light exerts its mutagenic effect by exciting electrons in molecules. The potent UV mutants which showed more than 20 mm zone of starch hydrolysis were screened and selected at 42% of survival time at 80minutes of exposure. The wild strain with fixed parameters yielded (3000 U/ml). The major findings of the strain improvement were out of ten mutants isolated, two (UV-3 and UV-10) showed 3000-4000 U/ml of amylase activity. The % of survival of Brevibacillus borstelensis R1 in Pikovskaya’s medium was 25.75% at 120 minutes of exposure. Ten mutants (HNO2-10, HNO2-30, EMS-4, EtBr-40, EtBr-50, Acr-1, Acr-20, Acr-30, Acr-4 and 5′-FU-50) out of fifty mutants isolated showed 3000-4300U/ml of amylase activity, which was higher than the wild strain. The potent Bacillus species screened from marine water was Brevibacillus borstelensis R1. The α-amylase was found to be useful in bakery, food, fodder for poultry, automation dishwashing and laundry industries.
Highlights
Strain improvementPhysical and chemical mutagens are promising and are used for screening of high yielding strains [1]
The potent Ultra violet (UV) mutants which showed more than 20 mm zone of starch hydrolysiswere screened and selected at 42% of survival time at 80 minutes of exposure (Figure 2)
Out of fifty mutants isolated ten mutants HNO2-10, HNO2-30, Ethyl methane sulfonate (EMS)-4, Ethidium bromide (EtBr)-40, EtBr-50, Acr-1, Acr-20, Acr-30, Acr-4 and 5׳-fluoro uracil (5׳-FU)-50 showed 1.32, 1.27, 1.38, 1.38, 1.34, 1.32, 1.35, 1.29, 1.41 and 1.22 fold increase in amylase activity, respectively which was higher than the wild strain (Table 2)
Summary
Strain improvementPhysical and chemical mutagens are promising and are used for screening of high yielding strains [1]. The yield may be increased by optimizing the cultural conditions, the productivity is controlled by the organism’s genome [2]. In the last few decades, the exponential increase in the application of amylases in various fields has placed stress and demand in both qualitative improvement and quantitative enhancement through strain improvement. Such improved strains reduce the cost of the process. Bacillus spp. such as B. subtilis and B. amyloliquefaciens are the most commonly used organisms of choice for amylase production [4,5]. It is worthwhile to select a potent microbial strain for α-amylase production
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