Identification of Native Microflora of Wheat Bran: Bacterial Isolates are Potential Industrial Producers

Background: At present, due to the conditions of deficiency of valuable nutrients, the development of technologies for the waste-free or low-waste production of new products based on by-products of grain processing is of particular interest. As a result of wheat grain processing, a significant amount of wheat bran is formed, which are of interest not only as components of feed substances, food raw materials, but also secondary raw materials for obtaining a number of compounds of various chemical nature and functional purposes useful for humans. According to literary sources, bran contains proteins, vitamins and dietary fiber, which are substrates for native microflora. In conditions of humidity other than normalized for the storage of wheat bran, microorganisms develop, which were mainly studied for safety. However, many representatives of the native microflora of wheat bran are of interest as potential industrial producers of food micro-ingredients and biologically active substances.

Purpose: To study the native microflora of wheat bran and identify isolates that are of interest as potential industrial producers. In this area, information in the literature covers mainly the taxonomic affiliation of the bran microbiome, so the study of the biosynthetic ability of its representatives is relevant.

Materials and Methods: For the identified microorganisms, a search was made for data from the literature on microorganisms that have biotechnological potential. In the course of research, the moisture content of wheat dietary bran was determined according to GOST 9404-88. To study the microflora of wheat dietary bran with high humidity (more than 7%), 2, 5 and 7-day fermentations were carried out in a shaker-incubator using the deep method; to obtain microbial isolates, the methods of surface and deep cultivation on a dense agar medium were used.

Results: The resulting pure cultures were identified by sequencing for the 16srRNA gene. The names of microorganisms were determined using the BLAST site. Among the identified 16 cultures, 7 cultures with a 7-day fermentation prevailed, followed by 6 cultures with a 5-day fermentation. Significantly fewer cultures were detected during 2-day fermentation (3 cultures). These results presumably indicate that the microorganisms identified as a result of 2-day fermentation secrete metabolites, which are a substrate for other microorganisms.

Conclusion: As a result of the research, bacterial isolates of wheat bran Arthrobacter agilis, Acinetobacter radioresistens, Rhizobium leguminosarum, Kocuria rhizopila, including probiotic representatives of the genus Enterococcus, were identified, promising for use as industrial producers of useful metabolites, in particular, enzymes, dyes, organic acids for use in the food industry, agriculture, medicine.
 

1. Ozdal, M., Ozlem, O. G., Sezen, A., Algur O. F.& Kurbanoglu E. B. (2017). Continuous production of indole-3-acetic acid by immobilized cells of Arthrobacter agilis. Biotech, 7, 1-6. https://doi.org/10.1007/s13205-017-0605-0

2. Ozdal, M., Ozdal, O. G. & Gurkok S. (2017). Statistical Optimization of Beta-Carotene Production by Arthrobacter agilis A17 Using Response Surface Methodology and Box-Behnken Design. II. International Conference on Advances in Natural and Applied Sciences, 1,1-5. https://doi.org/10.1063/1.4981749

3. Ram, N. S., Sonam G., Ajar N. Y., Prakhar G., Sneha G., Rajeev K. & Anil K. S. (2016). First high quality draft genome sequence of a plant growth promoting and cold active enzyme producing psychrotrophic Arthrobacter agilis strain L77. Standards in Genomic Sciences, 1, 1 – 9.https://doi.org/10.1186/s40793-016-0176-4

4. Raaman, N., Mahendran B., Jaganathan C., Sukumar S.& Chandrasekaran V. (2012). Removal of chromium using Rhizobium leguminosarum. World J Microbiol Biotechnol, 28, 627-636.https://doi.org/10.1007/s11274-011-0856-6

5. Sellami, M., Oszako T., Miled N. &Rebah F. B. (2015). Industrial wastewater as raw material for exopolysaccharide production by Rhizobium leguminosarum. Brazilian Journal of Microbiology, 46(2),407-413.http://dx.doi.org/10.1590/S1517-838246220140153

6. Tang, J. S., Patrick M. G.(2003). Reclassification of ATCC 9341 from Micrococcus luteus to Kocuria rhizophila. International Journal of Systematic and Evolutionary Microbiology, 53, 995-997.https://doi.org/10.1099/ijs.0.02372-0

7. Velazquez-Becerra, Cr., Macias-RodríguezL. I., Lopez-Bucio Jo., Flores-Cortez I., Santoyo G., Hernandez-Soberano Ch. & Eduardo Valencia-Cantero E.(2013). The rhizobacterium Arthrobacter agilis produces dimethylhexadecylamine, a compound that inhibits growth of phytopathogenic fungi in vitro. Springer. Protoplazma, 1, 100-112. https://doi.org/10.1007/s00709-013-0506-y

8. Wojciech, L., Choinska A., Rodziewicz A. & Piegza M. (2015). Keratinolytic abilities of Micrococcus luteus from poultry waste. Brazilian Journal of Microbiology, 46(3), 691-700. http://dx.doi.org/10.1590/S1517-838246320140098

9. Wojciech L., Zarowska B., Chorązyk D., Pudlo A., Piegza M., Kancelista A., & Kopec W. (2018). New keratinolytic bacteria in valorization of chicken feather waste. AMB Expr., 8(9), 1-14. https://doi.org/10.1186/s13568-018-0538-y

10. Yan, F., Lei W., Ajab K., Rui Z., Siang W.& Xiaoyuan J. (2020). Fermented wheat bran by xylanase-producing Bacillus cereus boosts the intestinal microflora of broiler chickens. Poultry Science, 99, 263 – 271.http://dx.doi.org/10.3382/ps/pez482