ISSN: 0973-7510

E-ISSN: 2581-690X

Research Article | Open Access
Cyr Jonas Morabandza1,4, Valentin Dibangou1,2, Faly Armel Soloka Mabika1,2 , Elgie Viennechie Gatse1,2, Tarcisse Baloki Ngoulou1,2, Ngo–Itsouhou1,2 and Etienne Nguimbi1,2,3
1Laboratoire de Biologie Cellulaire et Moleculaire, Faculte des Sciences et Techniques,
Universite Marien Ngouabi, Brazzaville, Republique du Congo.
2Unite de Microbiologie Moleculaire et Bioinformatique, Faculte des Sciences et Techniques, Universite Marien Ngouabi, Brazzaville, Republique du Congo.
3Institut de Recherche en Sciences Exactes et Naturelles (IRSEN), Avenue de l’auberge Gascogne Cite Scientifique (Ex. OROSTOM) Brazzaville, Republique du Congo.
4Ecole Normale Superieure, Universite Marien Ngouabi, Brazzaville, Republique du Congo.
J Pure Appl Microbiol. 2021;15(2):621-629 | Article Number: 6782 | © The Author(s). 2021
Received: 22/11/2020 | Accepted: 03/03/2021 | Published: 08/04/2021

The aim of this work was to determine the effect of a few external factors on bacterial growth and the production of enzymes with a proteolytic effect in three strains of Bacillus: CMS5 (Bacillus subtilis), CMS4 (Bacillus sp.) and SPo5 14′ (Bacillus velenzensis) isolated from squashes packed in traditionally prepared cassava leaves, but also to determine the best source of carbon and nitrogen. All three strains have the ability to actively degrade milk casein. The strains were grown in Luria Bertani medium and the suspension from the cell culture was used to measure optical density and demonstrate enzyme activity on a petri dish containing skim milk. Several parameters were verified including the influence of temperature, pH, and carbon and nitrogen source on growth and enzyme production. Growth was possible from 25 to 60°C with an optimal temperature of 30°C after 24 hours. Enzyme production was observed from 25 to 55°C with an optimum at 37°C. For pH, growth and enzyme production was possible from pH 5.7 and 9 with an optimum of 7 in all three strains. Among the sources of carbons used, galactose is the best source for growth after 24 h in all three strains, and starch for production. Among nitrogen sources, Bacto-peptone is best for growth as well as production.


Optimization, production, protease, strain, Bacillus

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© The Author(s) 2021. Open Access. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License which permits unrestricted use, sharing, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.