Tannin-tolerant and Extracellular Tannase Producing Bacillus Isolated from Traditional Fermented Tea Leaves and Their Probiotic Functional Properties

Abstract

A total of 117 Bacillus strains were isolated from Miang, a culture relevant fermented tea of northern Thailand. These strains were collected from 16 sampling sites in north Thailand. In this collection 95 isolates were tannin-tolerant Bacillus capable of growth on nutrient agar supplemented with 0.5% (w/v) total tannins from tea leaves extract (TE). The strains were also positive for pectinase, xylanase and amylase activity, while 91 and 86 isolates were positive for cellulase and β-mannanase, respectively. Only 21 isolates producing extracellular tannase were selected for further characterization. Identification by 16S rRNA gene sequence analysis revealed that more than 50% (11 of 21 isolates) were Bacillus tequilensis, whereas the remaining were B. siamensis (3), B. megaterium (3), B. aryabhattai (3) and B. toyonensis (1). B. tequilensis K34.2 produced the highest extracellular tannase activity of 0.60 U/mL after cultivation at 37 °C for 48 h. In addition, all 21 isolates were resistant to 0.3% (w/v) bile salt, sensitive to gentamicin, erythromycin, vancomycin and kanamycin and also tolerant to acidic condition. Cell hydrophobicity varied from 9.4 to 80.4% and neutralized culture supernatants of some Bacillus isolates showed bacteriocin producing potentiality against Samonella enterica serovar Typhimurium TISTR 292. All tested probiotic properties indicated that B. tequilensis K19.3, B. tequilensis K34.2 and B. siamensis K19.1 had high probiotic potential. This is the first report describing tannin-tolerant Bacillus and their extracellular tannase producing capability in Miang, a traditional fermented tea of Thailand.

Culturable Bacterial Community on Leaves of Assam Tea (Camellia sinensis var. assamica) in Thailand and Human Probiotic Potential of Isolated Bacillus spp.

“…A previous study described the probiotic properties and utilization of Bacillus [ 67 ]. In fermented Miang, B. tequilensis , B. siamensis , B. megaterium , B. toyonensis , and B. aryabhattai presented great probiotic potential [ 68 ]. Some Bacillus strains mentioned above could be also found in this study, suggesting a persistence of these bacteria from fresh to fermented leaves.…”

Probiotic and Antioxidant Properties of Lactic Acid Bacteria Isolated from Indigenous Fermented Tea Leaves (Miang) of North Thailand and Promising Application in Synbiotic Formulation

“…The LAB candidates showed higher surviving capability against in vitro gastrointestinal conditions than the L. acidophilus probiotic strain. Another consideration is that tea leaves contain phenolic compounds, particularly tannins and other tea phenolics, which are considered to inhibit microbial growth [14,16,46] and the microorganisms living and compatible in Miang substrate might have mechanisms allowing them to tolerate the tea tannins. In addition, the cell wall of L. plantarum and L. pentosus contain the meso-diaminopimelic acid (mDAP) peptidoglycan, which means they can survive in the tannin-rich substrate [14,16,18] and therefore potentially have greater survival capability against in vitro gastrointestinal conditions than the L. acidophilus probiotic strain.…”

Improvement of Enantiomeric l-Lactic Acid Production from Mixed Hexose-Pentose Sugars by Coculture of Enterococcus mundtii WX1 and Lactobacillus rhamnosus SCJ9

“…The molecular identification of LAB isolates was performed using the method described by Unban, et al [17]. Briefly, 10 mL of bacterial culture broth cultivated overnight at 37 • C were centrifuged at 12,000× g for 5 min.…”