Isolation, Molecular Identification and Evaluation of Antifungal Effect of Dominant Lactic Acid Bacteria Isolated from Wheat Bran and Rice Bran Sourdoughs
نویسندگان
1 Assistant Professor, Faculty of Food Technology, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran
2 Assistant Professor, Cereal Health Research Center, Golestan University of Medical Science, Gorgan, Iran
3 Former PhD Student of Food Microbiology, Faculty of Food Technology, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran
4 Former MSc Student of Food Biotechnology, Faculty of Food Technology, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran
5 Professor, Faculty of Food Technology, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran
doi
10.22101/JRIFST.2017.11.18.633چکیده
Sourdough is a proper fermented ecosystem for isolation of lactic acid bacteria (LAB) with antifungal effects. In this research, dominant LAB isolated from rice bran and wheat bran sourdoughs were identified based on molecular method. Antifungal activity of the isolates and their cell free culture filtrate (CCF) obtained from logarithmic and stationary phases were also investigated based on overlay and spore spot methods respectively, against Aspergillus flavus and Aspergillus niger. According to sequencing the results of PCR products, Lactobacillus paraplantarum in wheat bran sourdough and Pediococcus pentosaceus in rice bran sourdough were identified as dominant isolated LAB. The results of overlay method also confirmed the inhibitory potential of the isolates against indicator fungi in comparison to control sample. Furthermore, inhibitory effect of the LAB isolates against A. flavus was significantly higher than the A. niger (P<0.05). The inhibitory effect of CCF obtained from each bacterium logarithmic and stationary phases against A. flavus were also significantly different but between inhibitory effect of L. paraplantarum stationary CCF and P. pentosaceus logarithmic CCF against this fungus, significant difference was not observed (P<0.05). The inhibitory effect of CCF obtained from the isolates logarithmic and stationary phases against A. niger were also not significantly different (P<0.05).
