The Effect of Electromagnetism on Growth and Flocculation Potential of some selected Yeasts in Batch and Fed Batch Cultivation Systems

International Journal of Research and Innovation in Applied Science (IJRIAS) | Volume VI, Issue VII, July 2021|ISSN 2454-6194

The Effect of Electromagnetism on Growth and Flocculation Potential of some selected Yeasts in Batch and Fed Batch Cultivation Systems

Emmanuel Oluwasuen Garuba^1*, Motunrayo A. Adebowale² and Obinna Markraphael Ajunwa^3
1,2Microbial Physiology and Biochemistry Research Laboratory, Department of Microbiology, University of Ibadan, Ibadan, Nigeria
³Department of Microbiology, Modibbo Adama University of Technology, Yola, Nigeria
Correspondence Author*

Abstract : In this study, growth and flocculation potential of five different flocculent yeasts: Candida sphaerica OB10, Kluyveromyces marxianus OY11, Saccharomyces cerevisiae OGB1, Torulopsis stellate OGB3 and Candida kefyr OGB10 were investigated under electromagnetic condition in batch and fed batch cultivation systems. Candida sphaerica OB10 had optimum growth of 9.36 log cfu/mL under batch culture system followed by Saccharomyces cerevisiae OGB1 with 9.19 log cfu/mL and Kluyveromyces marxianus OY11 with growth of 7.72 log cfu/mL in fed-batch culture system; both without electromagnetic induction. Torulopsis stellata OGB3 under fed-batch system was 9.78 log cfu/mL after electromagnetic induction. Also, Candida kefyr OGB10 had an optimum growth of 10.14 log cfu/mL in fed-batch culture system. The results of the flocculation potential of the yeast isolates showed a reduction in flocculation potential in fed-batch culture system after electromagnetic induction as compared with fed batch system without electromagnetic induction while Candida sphaerica OB10, Kluyveromyces marxianus OY11, Torulopsis stellate OGB3 and Candida kefyr OGB10 had an increase in flocculation potential in batch culture system after electromagnetic induction. These results showed that the batch culture system which was steady and undisturbed was more important in yielding well coagulated and bottom settled cells in electromagnetically induced yeast fermentation systems when compared with the fed-batch system.

Keywords: Yeasts, Flocculation, Electromagnetism, Fed batch, Batch

I. INTRODUCTION

The non-sexual cell aggregation of yeasts also known as flocculation, although dates back to Pasteur scientific notes [1], its mechanism has raised much controversy in this last century [2]. This mechanism is reported to be mediated by interactions between the receptor – α-mannan carbohydrates which bind to cell surface lectin-like proteins (flocculins) which are found on adjacent both on flocculent and non-flocculent cells. This process is reported to be inhibited by EDTA or sugars, and restored by Ca2+ ions with the Ca2+ ions acting as cofactors to maintain the active conformation of surface proteins, thereby enhancing the capacity of lectins to interact with α-mannan carbohydrates [3].

Read More