Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XXIII
Written by Mihaela DUMITRU, Ionuț SORESCU, Mihaela HĂBEANU, Cristina TABUC, Ştefana JURCOANE
The purpose of this paper was to provide a direction for evaluating the probiotic potential and safety of a microbial strain in order to use in weaning piglets. Bacillus licheniformis ATCC 21424 was analyzed morphologically, culturally, biochemically, for hemolytic activity and enzymatically (amylase and protease screening). In vitro, some probiotic properties were study as: resistance to pH by simulated gastric juice (pH 2 and 3) and bile salts (simulated intestinal fluid). The biochemical characteristics was performed by catalase assay, API 50 CHB Biomerieux strips, apiweb API 50 CHB V 4.0 soft (B. licheniformis, % ID 99.9) and ABIS online (~90.6% similarity). The hemolytic activity was assayed on blood agar medium. The strain was grown in nutrient medium, in two ways: static incubation (37 C, 24 h, 4 x 108 CFU/ml) and under constant agitation (37 C, 24 h, 120 rpm, 1.56 x 1010 CFU/ml). To screen out, the most favorable carbon source was included in the basal medium (1% w/v, pH = 7) glucose (12.11 ± 0.1), fructose (11.73 ± 0.67), lactose (12.03 ± 0.14) and starch (12.51 ± 0.27). The strain is a Gram-positive, rod-shaped bacteria, arranged in short chains or in small irregular pairs with ability to produce spores. The endospores were central, paracentral and subterminal. The strain growth was aerobic and was non – hemolytic. The enzymatic process was observed by appearance of distinct zones around strain colonies. The strain presents relatively good viability at pH 3 and tolerated oxgall (0.3%). In conclusion, the results suggested that the strain present some probiotic traits and can be further assessed for other probiotic characters as antibacterial activity, induction of local immune response etc.
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