Bioactive Proteins Produced By Bacillus Subtilis Atcc 21332 And Lactobacillus Plantarum Atcc 8014 Under Antimicrobial Stress

• Main Author: Ismatul Nurul Asyikin Binti Ismail
• Format: Thesis
• Language: English
• Published: Universiti Sains Islam Malaysia 2015
• Subjects: Etil pentanoat; antimikrob semulajadi dan sintetik; Allium sativum; Sains dan Teknologi
• Online Access: http://ddms.usim.edu.my/handle/123456789/8494

Many reports indicate that antimicrobial agents or antibiotics at low concentrations are able to activate or repress gene transcription process in bacteria. However, there are still limited studies on the potential of natural antimicrobials at low doses acting as an inducer to trigger biological functions in bacteria. Therefore, the purpose of this study is to determine the potential of natural and synthetic antimicrobial compounds, which are Allium sativum and ethyl pentanoate at sub-minimal inhibitory concentration (sub-MIC) in inducing proteins production by Bacillus subtilis ATCC 21332 and Lactobacillus plantarum ATCC 8014. SDS-PAGE analysis showed that two extracellular proteins (with approximate size of 51.36 kD and 9.74 kD) were secreted by B. subtilis ATCC 21332 after being enhanced with A. sativum. Meanwhile, L. plantarum ATCC 8014 produced each three (which are 97.83 kD, 53.56 kD and 46.51 kD in size) as well as two (which are 46.51 kD and 6.91 kD in size) new intracellular proteins after being subjected to A. sativum and ethyl pentanoate subsequently. LC-MS/MS analysis presented that 25 proteins were expressed in mild stress condition and have been catalogued into 12 protein functional classes. The extracellular and intracellular proteins each produced by B. subtilis ATCC 21332 and L. plantarum ATCC 8014 revealed antimicrobial activity against selected Gram-positive and Gram-negative bacteria. Both extracellular and intracellular proteins were relatively heat- resistance at 25-30°C and heat-labile at temperature above 30°C. Hence, B. subtilis ATCC 21332 and L. plantarum ATCC 8014 in stressful condition with the presence of either A. sativum or ethyl pentanoate at sub-MIC level were able to induce the production of bioactive proteins with antimicrobial activity.