Functional traits of Selenium accumulating lactic acid bacteria as a probiont from fermented foods of an Indian tribal community

Abstract

In the present study, lactic acid bacteria (LAB) from the fermented foods of an Indian tribal community (Irulas) were isolated and screened for Selenium bio-accumulation. A total of 156 isolates were screened, and the isolate Se-M8 from the Khoji (fermented food prepared from the tuber Dioscorea sp.) accumulated 74.88 mg/L of Selenium. Se-M8 were identified as Enterococcus faecalis by 16S rRNA gene sequencing. This strain was screened for safety assessment, probiotic and antioxidant properties. It showed good tolerance to pH (2 and 3), bile salt (0.3 and 0.6%), transit tolerance, and firm adherence to mucin. It also inhibited the pathogenic biofilm formation by E. coli sturdily. The strain exhibited significant radical scavenging (DPPH֯ and ABTS֯) and strong reducing power activities. Accumulated Selenium particles were extracted, purified and characterised. TEM and SEM analysis revealed the presence of spherical shape particles of 1 μM diameter. This is the first report on the Selenium bio-accumulation by an Enterococcus faecalis strain. Hence, the strain Se-M8 could be used as probiotics with the additional functional role of Selenium supplement to the well-being of human and animal health. Selenium-enriched functional food products could be used as a source of dietary Selenium supplementation for Selenium deficiency disorders and their associated complications.

Keywords

• Fermented foods
• Lactic acid bacteria
• Enterococcus faecalis
• Selenium accumulation
• Probiotics
• Functional traits