Statistical optimization for enhanced yields of probiotic Bacillus coagulans and its phage resistant mutants followed by kinetic modelling of the process.

Kavita R Pandey,Babu V Vakil,Chetan Joshi

doi:10.1186/s40064-016-3325-8

Kavita R Pandey, Babu V Vakil + Show 1 more

Open Access

https://doi.org/10.1186/s40064-016-3325-8

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Journal: SpringerPlus	Publication Date: Sep 23, 2016
Citations: 2	License type: CC BY 4.0

Affiliation: Institute of Chemical Technology

Abstract

Probiotics are microorganisms which when administered in adequate amounts confer health benefits to the host. A leading pharmaceutical company producing Bacillus coagulans as a probiotic was facing the problem of recurring phage attacks. Two mutants viz. B. co PIII and B. co MIII that were isolated as phage resistant mutants after UV irradiation and MMS treatment of phage sensitive B. coagulans parental culture were characterized at functional and molecular level and were noted to have undergone interesting genetic changes. The non-specific genetic alterations induced by mutagenesis can also lead to alterations in cell performance. Hence, in the current study the parental strain and the two mutants were selected for shake flask optimization. Plackett–Burman design was used to select the significant culture variables affecting biomass production. Evolutionary operation method was applied for further optimization. The study showed wide variations in the nutritional requirements of phage resistant mutants, post exposure to mutagens. An increment of 150, 134 and 152 % was observed in the biomass productions of B. coagulans (parental type) and mutants B.co PIII and B.co MIII respectively, compared to the yield from one-factor-at-a-time technique. Using Logistic and modified Leudeking–Piret equations, biomass accumulation and substrate utilization efficiency of the bioprocess were determined. The experimental data was in agreement with the results predicted by statistical analysis and modelling. The developed model may be useful for controlling the growth and substrate consumption kinetics in large scale fermentation using B. coagulans.

Highlights

Probiotics have been defined jointly by FAO and WHO as “Live microorganisms which when administered in adequate amounts confer a health benefit to the host” (FAO Joint2007)
Using Plackett Burman (PB) methodology, three most significant variables influencing biomass production were identified for the three probiotic cultures viz. glucose concentration, C/N ratio and agitation speed
Evolutionary operation (EVOP) was applied to the data obtained by PB-design to predict the optimum conditions leading to maximal biomass formation

Summary

Introduction

Probiotics have been defined jointly by FAO and WHO as “Live microorganisms which when administered in adequate amounts confer a health benefit to the host” (FAO Joint2007). Random mutagenesis was employed to obtain seven phage resistant mutants from the phage sensitive probiotic culture—Bacillus coagulans (Dubey and Vakil 2012). These mutants displayed variations in functional attributes in comparison to the parental culture (Pandey et al 2015). Partial 16SrRNA sequences of the mutants were provided with unique accession numbers by GenBank (Pandey et al 2015) These alterations can be attributed to the use of mutagens which in turn might have introduced random mutations at multiple points throughout the DNA (Pandey et al 2015). Optimization of the medium composition and process conditions was considered necessary for the mutants

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Conclusion