Molecular Identification of Bacillus Species during Spontaneous Fermentation of Lima Bean Flour (Phaseolus lunatus)

Aims: Bacillus species is used as starter culture to improve quality of the fermented product. Thus, the purpose of this study is to identify Bacillus species during the spontaneous fermentation of Phaseolus lunatus with prospective selection as starter cultures.

Study Design: Spontaneous fermentation of Phaseolus lunatus flour was allowed to proceed at ambient temperature (29±2°C) for three days under anaerobic condition.

Methodology: The Bacillus counts were determined and 100 isolates were identified by PCR and the sequencing of 16S rDNA domain.

Results: In unfermented sample the Bacillus count was 3.14 log CFU/mL. During fermentation the count being between 2.68 and 2.88 log CFU/mL. Based on PCR and the sequencing of 16S rDNA domain, Bacillus isolates were assigned to four species Bacillus sp, Bacillus subtilis, Brevibacillus agri and Bacillus xiamensisis. Bacillus spp, Bacillus subtillis and Bacillus cereus were detected at all the fermentation times. Their frequencies were between 14.29 and 45.83%, 25 and 35.71%, 25 and 50% respectively.

Conclusion: Among these species Bacillus subtillis could be used as starter culture to improve quality of the fermented product.