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Isolation, identification and potential probiotic characterization of lactic acid bacteria from Thai traditional fermented food

  • The probiotic potential of lactic acid bacteria (LAB) isolated from Thai traditional fermented food was investigated. Forty-two samples were collected from four markets in Phra Nakhon Si Ayutthaya Province. Out of 50 isolated LAB, 6 (a3, f4, f8, K1, K4 and K9) obtained from pla-ra and bamboo shoot pickle samples showed high tolerance to gastrointestinal tract conditions. These isolates were selected to identify and characterize their probiotic properties. Isolate a3 was identified as Weissella thailandensis, isolates f4 and f8 were identified as belonging to Enterococcus thailandicus and isolates K1, K4 and K9 were determined as Limosilactobacillus fermentum. All six LAB exhibited high autoaggregation ability (93.40–95.01%), while W. thailandensis isolate a3 showed potential for coaggregation in almost all the pathogenic bacteria tested. Cell-free supernatant (CFS) obtained from all isolates did not inhibit Staphylococcus aureus. CFS derived from L. fermentum isolate K4 showed the most efficient antimicrobial activity, in particular against Gram-negative bacteria, while L. fermentum isolate K4 presented high surface hydrophobicity in the presence of xylene and n-hexane. All LAB isolates were found to be resistant to clindamycin and nalidixic acid, whereas E. thailandicus isolate f8 exhibited resistance to most of the antibiotics tested. L. fermentum isolate K4 showed promise as a suitable probiotic candidate for future applications in the food industry due to tolerance to gastrointestinal tract conditions with high surface hydrophobicity and inhibited most of the pathogens tested.

    Citation: Sunisa Suwannaphan. Isolation, identification and potential probiotic characterization of lactic acid bacteria from Thai traditional fermented food[J]. AIMS Microbiology, 2021, 7(4): 431-446. doi: 10.3934/microbiol.2021026

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  • The probiotic potential of lactic acid bacteria (LAB) isolated from Thai traditional fermented food was investigated. Forty-two samples were collected from four markets in Phra Nakhon Si Ayutthaya Province. Out of 50 isolated LAB, 6 (a3, f4, f8, K1, K4 and K9) obtained from pla-ra and bamboo shoot pickle samples showed high tolerance to gastrointestinal tract conditions. These isolates were selected to identify and characterize their probiotic properties. Isolate a3 was identified as Weissella thailandensis, isolates f4 and f8 were identified as belonging to Enterococcus thailandicus and isolates K1, K4 and K9 were determined as Limosilactobacillus fermentum. All six LAB exhibited high autoaggregation ability (93.40–95.01%), while W. thailandensis isolate a3 showed potential for coaggregation in almost all the pathogenic bacteria tested. Cell-free supernatant (CFS) obtained from all isolates did not inhibit Staphylococcus aureus. CFS derived from L. fermentum isolate K4 showed the most efficient antimicrobial activity, in particular against Gram-negative bacteria, while L. fermentum isolate K4 presented high surface hydrophobicity in the presence of xylene and n-hexane. All LAB isolates were found to be resistant to clindamycin and nalidixic acid, whereas E. thailandicus isolate f8 exhibited resistance to most of the antibiotics tested. L. fermentum isolate K4 showed promise as a suitable probiotic candidate for future applications in the food industry due to tolerance to gastrointestinal tract conditions with high surface hydrophobicity and inhibited most of the pathogens tested.



    In this note we consider the following magnetic, quantum Euler equations:

    {tρ+divJ=0tJ+div(JJρ)+P(ρ)=JB+12ρ(Δρρ), (1.1)

    in the unknowns (ρ,J):Rt×R3R0×R3, representing the charge and current densities of a positively charged quantum fluid, interacting with an external, time-independent magnetic field B. The third order nonlinear term in the right hand side of the momentum balance encodes the quantum correction, while JB is the magnetic force associated to the field B (we are neglecting here the self-induced electromagnetic field). We assume B=A for some real-valued, divergence-free potential A. Finally, P(ρ) is a barotropic pressure term, which assumes the form P(ρ)=γ1γργ, with γ>1. From now on, we focus without loss of generality only on forward-in-time solutions (i.e., defined for t0) and we denote the initial data at time t=0 by (ρ0,J0).

    System (1.1), as well as suitable variations, arise in the description of hydrodynamic models in which the quantum statistic becomes relevant at mesoscopic/macroscopic scales, which happens when the thermal de Broglie wavelength is comparable to (i.e., larger than or equal to) the average interatomic distance [1]; important examples include superfluidity [2], quantum plasma [3], and nanoscale semiconductor devices [4]. Since the constituent particles (e.g. fermions, such as electrons, and bosons as the Cooper pairs in superconductivity [5]) of a quantum fluid are typically charged, in many situations it becomes necessary to account for electromagnetic effects in the hydrodynamic description. A relevant model is provided by the quantum Euler-Maxwell equations, which describe the dynamics of a positively charged quantum fluid interacting with its self-induced electromagnetic field, see [5,6,7,8] and references therein for a comprehensive analysis.

    On the other hand, as in the classical Ginzburg-Landau theory of superconductivity, the presence of an external magnetic field (especially of large amplitude) can drastically affect the behavior (both dynamical and at equilibrium) of a quantum fluid, even when the self-generated electromagnetic field may be neglected. In this perspective, we mention the work [9], which deals with a quantum fluid model for spinning fermions under the influence of an external electromagnetic field and discusses several applications, including quantum X-ray free-electron lasers and micro-mechanical systems. We also point out that in [9] the quantum fluid equations are not only introduced as effective model, but they are also formally derived from a microscopic, many-body description. In fact, an important issue in hydrodynamic and condensed-matter physics concerns the possibly rigorous derivation of effective equations from first principles. In this direction we mention [10], which gives a rigorous derivation of the incompressible 2D Euler equation from the von Neumann equation with an external magnetic field, and [11] where a 3D quantum fluid model with self-induced electromagnetic field is derived from the bosonic Pauli-Fierz Hamiltonian.

    In the search for a rigorous derivation of a quantum hydrodynamic model, a preliminary (yet crucial) step is to have at hand a suitable solution theory, possibly at the whole finite-energy level (i.e., without requiring any extra regularity or smallness assumption on the initial data). Moreover, in order to deal with physically meaningful solutions, all the corresponding observables should be well defined.

    Motivated by the above discussion, in this paper we aim to construct finite energy solutions to the magnetic quantum Euler equations (1.1) (without restrictions on the size of the initial data) such that the magnetic force JB is well-defined. We will deal only with weak solutions, since this allows us to consider a wide class of (possibly large and non-smooth) magnetic fields, see Remark 2.2.

    System (1.1) admits two quantities that are formally preserved along the flow: the total charge ρL1=ρ2L2 and the total energy

    E(t)=12R3|ρ|2+|Λ|2+2f(ρ)dx, (1.2)

    where Λ:=Jρ and f(ρ):=ργγ is the internal energy density. Observe that, for γ3, we have f(ρ)L1(R3) whenever ρH1(R3). We restrict to the subcritical regime γ<3, while the critical case γ=3 requires a slightly finer analysis, which for concreteness will not be addressed here. Then, in view of System (1.2), the natural finite-energy condition for solutions to System (1.1) is

    ρH1(R3),ΛL2(R3).

    We work in a quasi-irrotational framework. More precisely, for almost every time we require the generalized irrotationality condition

    J+ρB=2ρΛ (1.3)

    to be satisfied as an identity in D(R3). In order to clarify the meaning of the above condition, consider a smooth solution (ρ,J) to System (1.1), for which we can define the velocity field v through the relation J=ρv. A direct computation then shows that System (1.3) is equivalent to the identity

    ρ(v+B)=0,

    which implies in particular that the relative velocity field vA:=v+A is irrotational outside vacuum, namely vA=0 on {ρ>0}. On the other side, condition (1.3) is compatible with the occurrence of quantum vortices, namely solutions such that vA has non-zero (quantized) circulations around a vacuum region. Formation of vortices plays a fundamental role in the study of quantum fluids [12], hence the importance of developing a theory which embodies solutions carrying a non-trivial vorticity.

    Our last requirement is that a solution to System (1.1) must be regular enough to provide a meaning (e.g., local integrability) to the magnetic force JB. It is worth pointing out that the finite-energy condition alone does not provide a priori a well-defined magnetic force. Indeed, by Sobolev embedding and Hölder inequality,

    (ρ,Λ)H1(R3)×L2(R3)J=ρΛL32(R3),

    which guarantees that JB is locally integrable only when BL3loc(R3). We will be able instead, by means of suitable a priori space-time dispersive estimates, to deal with magnetic fields that are almost finite-energy, namely BL2+(R3).

    As anticipated, the goal of this note is to show the existence of global in time, finite-energy, weak solutions to System (1.1), without assuming any smallness condition on the initial data. Motivated by the above discussion, we provide the rigorous notion of solution. To this aim, observe that the convective term in the momentum equation can be rewritten as

    ρ1(JJ)=ΛΛ, (1.4)

    while the quantum term can be written in divergence form as

    12ρ(Δρρ)=div(142ρρρ). (1.5)

    Definition 1.1. Let 0<T, ρ0,J0L1loc(R3). We say that (ρ,J) is a finite-energy weak solution to System (1.1) on the space-time slab [0,T)×R3, with initial data (ρ0,J0), if the following conditions are satisfied:

    (i) (finite energy hydrodynamic state) there exists a pair (ρ,Λ), with ρLloc(0,T;H1(R3)) and ΛLloc(0,T;L2(R3)), such that ρ=(ρ)2, J=ρΛ;

    (ii) (continuity and momentum equations - weak formulations) for every ηCc([0,T)×R3) and ζCc([0,T)×R3;R3),

    T0R3ρtη+Jηdxdt+R3ρ0(x)η(0,x)dx=0; (1.6)
    T0R3Jtζ+ζ:(ρρ+ΛΛ)+(JB)ζ14ρΔdivζ+P(ρ)divζdxdt+R3J0(x)ζ(0,x)dx=0; (1.7)

    (iv) (well-defined magnetic force) JBL1loc((0,T)×R3);

    (v) (generalized irrotationality condition) for a. e. t(0,T), the generalized irrotationality condition (1.3) holds true in D(R3).

    When T= we say that the solution is global.

    The quantum term in System (1.1) induces a quadratic dispersion relation in the irrotational part of the flow, as can be readily verified by linearizing around a constant state. Nevertheless, this enhanced dispersion (comparing with the linear dispersion of the classical Euler equations) is still not sufficient to directly derive suitable a priori bounds and prove the existence of solutions for large, finite energy initial data. We exploit instead a suitable wave-function dynamics associated to System (1.1). More precisely, if a complex-valued function ψ satisfies the magnetic NLS equation

    itψ=12ΔAψ+f(|ψ|2)ψ, (2.1)

    where ΔA:=AA:=(iA)(iA)=Δ2iA|A|2 is the magnetic Laplacian, then its Madelung transform

    ρ=|ψ|2,J=Im(¯ψAψ) (2.2)

    formally solves System (1.1). Suppose indeed that we can write ψ=ρeiθ so that J=ρ(θA) for smooth functions ρ,θ, with ρ>0. Substituting this ansatz into the NLS (2.1), and separating real and imaginary part, we obtain a system of equations that reduces after some manipulations to System (1.1).

    The connection between quantum fluid models and wave-functions dynamics governed by Schrödinger-type equations, originally observed in the seminal work by Madelung [13], has been widely exploited in the mathematical literature: we mention [14,15] and [16,17,18,19,20], see also [21] and references therein.

    In particular, the existence of global, finite-energy solutions for the 3D quantum Euler equations (i.e., System (1.1) without the magnetic component JB in the momentum balance) has been proved in [14], for arbitrarily large initial data and allowing for vacuum. In this case, the corresponding wave-function dynamics is governed by the semilinear NLS

    itψ=12Δψ+f(|ψ|2)ψ, (2.3)

    for which a satisfactory well-posedness theory at the finite energy level (i.e., H1-regularity) is available (see e.g., the monograph [22] and references therein). Still, the precise construction of the hydro-dynamic variables and the rigorous derivation of the quantum Euler equations require a fine analysis, based upon the polar factorization technique (see the discussion in Section 3). Existence of global weak solutions has been also proved for aforementioned quantum Euler-Maxwell equations [23], see also [24]. The wave-function dynamics is given now by a nonlinear Maxwell-Schrödinger (MS) system, for which well-posedness is available only above the finite energy level [25]. Still, relying on the existence of finite energy weak solutions to MS [26] and suitable a priori estimates, in [23] the quantum Euler-Maxwell equations are derived by directly working with the weak formulations. This approach has been adopted in [18] for the quantum Euler equations, and is in turn inspired by ideas in [27,28]. Here, we will follow an analogous strategy.

    In order to state our main result, we first need some assumptions. Concerning the magnetic potential A, we impose the following condition:

    AL(R3)Hσ(R3)for some σ>1. (2.4)

    As anticipated, in terms of the magnetic field B=A we are just above the finite-energy level BL2(R3). The extra integrability assumption on A will be crucial to obtain the appropriate a priori estimates (see Proposition 3.1) for weak solutions to the magnetic NLS (2.1). In addition, Condition (2.4) guarantees [29, Lemma 2.4] that the magnetic Sobolev space

    H1A(R3):={ψL2(R3):AψL2(R3)},ψH1A=ψL2+AψL2,

    coincides (with equivalence of norms) with the classical Sobolev space H1(R3). Since the energy of the magnetic NLS (2.1) is given by

    E(t)=12R3|Aψ|2+2f(|ψ|2)dx, (2.5)

    we then deduce (in the sub-critical regime γ<3) that H1(R3) is the energy space for Eq (2.1).

    Concerning the initial data (ρ0,J0), we impose that they are the Madelung transform of a finite energy wave function:

    ρ0=|ψ0|2,J0=Im(¯ψ0Aψ0) for some ψ0H1(R3). (2.6)

    The above condition is natural from the quantum mechanics perspective, as it is equivalent [30] to assume that the (relative) initial velocity field v0,A has quantized circulations around vacuum, namely

    γv0,Ads2πZ (2.7)

    for any closed, smooth path in ρ>0.

    We are now able to state our main result.

    Theorem 2.1. Assume that the magnetic potential A and the initial data (ρ0,J0) satisfy Systems (2.4) and (2.6), respectively. Then there exists a global, finite energy weak solution to System (1.1), in the sense of Definition 1.1.

    Remark 2.2. The existence of strong (i.e., continuous in time) solutions to System (1.1) is unknown in general. Indeed, the typical dispersive bounds, such as Strichartz estimates, which would guarantee the well-posedness in H1(R3) of the corresponding NLS (2.1) are available only for some restricted class of magnetic potentials, satisfying either smoothness, smallness, or non-resonant assumptions (see e.g., [31,32,33] and references therein).

    Remark 2.3. In the case of the quantum Euler-Maxwell equations, the L-bound (suitably averaged over time) on A follows by means of the dispersive estimates for its wave-type evolution, as soon as the initial magnetic potential is slightly more regular than finite energy. Here, dealing with a fixed, external magnetic field, such condition is imposed a priori. An interesting open question that arises is whether the integrability assumption on A could be weakened without imposing any extra smallness, regularity or spectral condition. This would require new technical ideas to deal with the derivative term 2iA in the expansion of the magnetic Laplacian.

    The solution constructed in Theorem 2.1 will be obtained as Madelung transform of a time-dependent wave-function satisfying System (2.1). As such, the quantized vorticity condition will be automatically satisfied at (almost every) time.

    Finally, we mention that it would be possible to prove a weak-stability result for System (1.1), in the same spirit of [23,Theorem 1.3]. For the sake of concreteness, we do not pursue this direction here.

    The next section is devoted to the proof of Theorem 2.1. We preliminary fix some notations. We will write AB if ACB for some C>0, and AkB if the above constant C depends on the parameter k. Given s>0, p1, we denote by Hs,p(R3) the classical Sobolev (Bessel-potential) space. Given p[1,], T>0 and a Banach space X, we write LpTX to denote the Bochner space Lp((0,T);X).

    Our starting point is the existence of a global, finite energy weak solution

    ψLloc(R,H1(R3))W1,loc(R,H1(R3)) (3.1)

    to the magnetic NLS (2.1), with initial data ψ0. This has been proved in [29, Theorem 1.2], where a wider class of rough, time-dependent magnetic potentials is actually considered.

    We are going to show that the Madelung transform (ρ,J) of ψ, defined by System (2.2), is a global, finite energy, weak solution to System (1.1), in the sense of Definition (1.1). There are two main issues.

    First of all, since the velocity field v is not well-defined on the vacuum regions, the hydrodynamic variable Λ, formally given by Λ=ρv, needs to be carefully realized. To this aim, we briefly recall the polar factorization technique (see e.g., [24]). Consider the set

    P(ψ):={φL(R3) s.t. φL1,ψ=|ψ|φ a.e. in R3} (3.2)

    of polar factors of ψ. Given φP(ψ), let us define

    Λ=Im(ˉφAψ)L2(R3).

    Since Aψ=0 almost everywhere on {ρ=0} [24, Theorem 6.19], the above definition tells us that the Λ is uniquely defined, with Λ=0 on the vacuum. As a consequence, the identity J=ρΛ and formulas (1.4) and (1.5) are rigorously justified, and we deduce that the energy (1.2) of the hydrodynamic state (ρ,Λ) coincides with the energy (2.5) of the wave function ψ.

    The second issue is related to the rigorous derivation of System (1.1) from the corresponding NLS Equation (2.3), which could be directly justified only for sufficiently regular (above the finite energy level) wave functions. Since we can not appeal to the H1(R3)-stability (recall indeed that the well-posedness in H1(R3) for System (2.3) is unknown in general, as discussed in Remark 2.2), we can not rely on any approximation procedure. We derive instead the weak formulations (1.6) and (1.7) of System (1.1) directly from the Duhamel (integral) formula of System (2.3). To this aim, we need a suitable a priori estimate, similar to [23, Proposition 3.1].

    Proposition 3.1. For any T(0,) it holds the estimate

    ψL2TH1/2,6T1. (3.3)

    Proof. In view of the Koch-Tzvetkov type estimates [25, Lemma 2.4] and the classical inhomogeneous Strichartz estimate [34] for the Schrödinger equation, we deduce

    ψL2TH12,6TψLTH1+Aψ+|A|2ψL2TL2+f(|ψ|2)ψL2TH12,65.

    Using assumptions (2.4) on A we get

    Aψ+|A|2ψL2TL2TALψLTH1.

    Moreover, since γ<3, a direct application of Sobolev embedding, Gagliardo-Niremberg and Hölder inequalities yields

    f(|ψ|2)ψL2TH12,65=|ψ|2(γ1)ψL2TH12,65Tψ1+εLTH1ψ1εL2TH12,6

    for some ε=ε(σ)(0,1). Since ψLTH1T1, we then obtain

    ψL2TH12,6T1+ψ1εL2TH12,6,

    which implies Eq (3.3), as desired.

    Remark 3.2. The above argument can be rigorously justified by considering a sufficiently regular ψ, for which the finiteness of ψL2TH12,6 is guaranteed, and then appealing to a standard density argument. Alternatively, one could exploit a bootstrap procedure as in [23, Proposition 3.1].

    We can prove now that the pair of hydrodynamic variables (ρ,J) satisfies conditions (ⅰ)–(ⅳ) of Definition (1.1), with T=.

    (ⅰ) Since the map ψ(ρ,Λ) is bounded (and actually continuous) [24, Lemma 5.3] from H1(R3) into H1(R3)×L2(R3), we then deduce from Eq (3.1) that

    (ρ,Λ)Lloc(R,H1(R3)×L2(R3)).

    (ⅱ) The weak formulations of the continuity and momentum equations can be obtained following the same lines as in [23, Section 4]: The extra-integrability (almost L) on ψ provided by Eq (3.3), and the extra-regularity (above finite energy) on B assumed in (2.4) allow in fact to rigorously justify the derivation of Eqs (1.6) and (1.7) from the integral (Duhamel) formulation of the magnetic NLS (2.1).

    (ⅲ) In view of Sobolev embedding, Hσ1(R3)Lp(R3) and H12,6(R3)Lq(R3), for suitable p>2 and q< such that 1p+1q=12. Then, for every T>0,

    JBL1TL1TψL2TLqψLTL2BLp+ψ2LTL4ALBL2ψL2TH12,6ψLTH1AHσ+ψ2LTH1ALH1T1,

    which implies in particular JBL1loc(R×R3).

    (ⅳ) We start by observing that

    J=Im(ˉψψ)|ψ|2AB|ψ|2,

    which yields

    J+ρB=Im(ˉψψ)2ρρA. (3.4)

    On the other hand, given a polar factor φ of ψ, we have

    2ρΛ=2ρIm(ˉφψ)2ρ(Aρ). (3.5)

    Moreover, we have the chain of identities

    Im(ˉψψ)=2Im(ˉφρρϕ)=2ρIm(ˉφψ). (3.6)

    Combining Eqs (3.4)–(3.6), we deduce that the generalized irrotationality condition (1.3) is satisfied for almost every time as a distributional identity.

    The proof of Theorem 2.1 is complete.

    We have shown how to construct global, finite energy weak solutions to a quantum fluid system with an external (possibly large and non-smooth) magnetic field, following similar lines as in the case of the quantum Euler-Maxwell system. Analogous arguments can be also used to deal with the case when both an external magnetic field and the self-induced electromagnetic fields are taken into account in the dynamics of a charged quantum fluid. Finally, let us point out that the overall strategy exploited in this work appears to be versatile and could potentially be adapted to deal with more general dispersive hydrodynamic models, whose solution theory is still not well understood. A relevant example is provided by the Euler-Korteweg system

    {tρ+div(ρv)=0,t(ρv)+div(ρvv)+p(ρ)=ρdiv((k(ρ)ρ)12k(ρ)|ρ|2), (4.1)

    where k(ρ)0 is the capillarity coefficient. System (4.1) arises, among the others, in the description of capillarity effects in diffuse interfaces [35]. The choice k(ρ)=14ρ leads in particular to the quantum Euler equations. Also, the Euler-Korteweg system is connected, through the Madelung transform, to a wave-function dynamics, given in this case by the quasi-linear NLS

    itψ=12Δψdiv(˜k(|ψ|2)|ψ|2)ψ+12˜k(|ψ|2)||ψ|2|2ψ+f(|ψ|2)ψ, (4.2)

    where ˜k(ρ)=k(ρ)14ρ. Comparing with the magnetic NLS (2.1), where the Laplace operator is perturbed by the derivative term 2iA, in Eq (4.2) there appears a second-order term with non-constant and ψ-dependent coefficient, which makes it even harder to prove suitable dispersive estimates. In fact, the global well-posedness for the 3D Euler-Korteweg system is only known under the strong ellipticity condition ρ˜k(ρ)c>0 at sufficiently high regularity (Hs with s>72), without vacuum, and for small, spatially localized initial data [36]. On the other side, it is conceivable that weak H1-solutions to System (4.2) can be constructed by means of compactness arguments and in turn that low regularity, weak solutions to the Euler-Korteweg system can be derived by exploiting the strategy presented here, which only relies upon dispersive estimates with loss of derivatives.

    The author declares he has not used Artificial Intelligence (AI) tools in the creation of this article.

    The author would like to thank the anonymous referees for the useful suggestions. The author acknowledges support to INdAM-GNAMPA through the project "Local and nonlocal equations with lower order terms".

    The author declares there is no conflict of interest.


    Acknowledgments



    The author would like to thank graduate student Miss Suteema Phanit who kindly assisted in data collection and analysis.

    Conflict of interest



    The author declares no conflicts of interest.

    [1] Fontana L, Bermudez-Brito M, Plaza-Diaz J, et al. (2013) Sources, isolation, characterization and evaluation of probiotics. Br J Nutr 109: 35-50.
    [2] Hartayanie L, Lindayani, Murniati MP (2016) Antimicrobial activity of Lactic acid bacteria from bamboo shoot pickles fermented at 15 °C. Microbiol Indones 10: 71-77.
    [3] Ayyash M, Liu SQ, Mheiri AA, et al. (2019) In vitro investigation of health-promoting benefits of fermented camel sausage by novel probiotic Lactobacillus plantarum: A comparative study with beef sausage. LWT-Food Sci Technol 99: 346-354.
    [4] Yongsmith B, Malaphan W (2016) Traditional Fermented Foods in Thailand. Traditional Foods New York: Springer Science+Business Media, 31-58.
    [5] FAO/WHO FAO/WHO working group report on drafting guidelines for the evaluation of probiotics in food, London, Ontario, Canada, April 30 and May 1, World Health Organization (2002) .Available from: https://www.who.int/foodsafety/\fs_management/en/probiotic_guidelines.pdf.
    [6] Abulfazl B (2012) Isolation and molecular study of potentially probiotic lactobacilli in traditional white cheese of Tabriz in iran. Ann Biol Res 3: 2213-2216.
    [7] Arshad FA, Mehmood R, Hussain S (2018) Lactobacilli as probiotics and their isolation from different sources. Br J Res 5: 1-11.
    [8] Gibson GR, Hutkins R, Sanders ME, et al. (2017) The International scientific association for probiotics and prebiotics (ISAPP) consensus statement on the definition and scope of prebiotics. Expert Consensus Statement 14: 491-502.
    [9] Musikasang H, Tani A, H-kittikun A, et al. (2009) Probiotic potential of lactic acid bacteria isolated from chicken gastrointestinal digestive tract. World J Microbiol Biotechnol 25: 1337-1345.
    [10] Ranadheera RDCS, Baines SK, Adams MC (2010) Importance of food in probiotic efficacy. Food Res Int 43: 1-7.
    [11] Sivamaruthi BS, Kesika P, Chaiyasut C (2018) Thai fermented foods as a versatile source of bioactive microorganisms-A comprehensive review. Sci Pharm 86: 2-11.
    [12] Yadav R (2017) Probiotics for Human Health. Current Progress and Applications. Recent advances in Applied Microbiology Singapore: Springer, 133-147.
    [13] Soccol CR, Vandenberghe LPDS, Spier MR, et al. (2010) The potential of probiotics: A review. Food Technol Biotechnol 48: 413-434.
    [14] Hoque MZ, Akter F, Hossain KM, et al. (2010) Isolation, identification and analysis of probiotic properties of Lactobacillus spp. From selective regional yoghurts. World J Dairy Food Sci 5: 39-46.
    [15] Arboleya S, Ruas-Madiedo P, Margolles A, et al. (2011) Characterization and in vitro properties of potentially probiotic Bifidobacterium strains isolated from breast-milk. Int J Food Microbiol 149: 28-36.
    [16] Re BD, Sgorbati B, Miglioli M, et al. (2000) Adhesion, autoaggregation and hydrophobicity of 13 strains of Bifidobacterium longumLett Appl Microbiol 31: 438-442.
    [17] Guan C, Chen X, Jiang X, et al. (2020) In vitro studies of adhesion properties of six lactic acid bacteria isolated from the longevous population of China. RSC Adv 10: 24234-24240.
    [18] Tagg JR, McGiven AR (1971) Assay system for bacteriocins. Appl Microbiol 21: 943.
    [19] Charteris WP, Kelly PM, Morelli L, et al. (1998) Antibiotic susceptibility of potentially probiotic Lactobacillus species. J Food Prot 61: 1636-1643.
    [20] Miyashita M, Yukphan P, Chaipitakchonlatarn W, et al. (2012) 16S rRNA gene sequence analysis of lactic acid bacteria isolated from fermented foods in Thailand. Microbiol Cult Coll 28: 1-9.
    [21] Rodpai R, Sanpool O, Thanchomnang, et al. (2021) Investigating the microbiota of fermented fish products (Pla-ra) from different communities of northeastern Thailand. PLos One 16: e0245227.
    [22] Thakur K, Rajani CS, Kumar S, et al. (2016) Fermented bamboo shoots: a riche niche for beneficial microbes. J Bacteriol Mycol 2: 87-93.
    [23] Lindayani L, Hartayanie L, Murniati MP (2018) Probiotic potential of lactic acid bacteria from yellow bamboo shoot fermentation using 2.5% and 5% brine at room temperature. Microbiol Indones 12: 30-34.
    [24] Mir SA, Raja J, Masoodi FA (2018) Fermented vegetables, a rich repository of beneficial probiotics-a review. Ferment Technol 7: 1-6.
    [25] Ben SR, Trabelsi I, Ben MR, et al. (2012) A new Lactobacillus plantarum strain, TN8, from the gastro intestinal tract of poultry induces high cytokine production. Anaerobe 18: 436-444.
    [26] Tanasupawat S, Shida O, Okada S, et al. (2000) Lactobacillus acidipiscis sp. nov. and Weissella thailandensis sp. nov., isolated from fermented fish in Thailand. Int J Syst Evol 50: 1479-1485.
    [27] Tanasupawat S, Sukontasing S, Lee JS (2008) Enterococcus thailandicus sp. nov., isolated from fermented sausage (‘mum’) in Thailand. Int J Syst Evol 58: 1630-1634.
    [28] Chen YS, Wu HC, Liu CH, et al. (2010) Isolation and characterization of lactic acid bacteria from jiang-sun (fermented bamboo shoots), a traditional fermented food in Taiwan. J Sci Food Agric 90: 1977-1982.
    [29] Behera P, Balaji S (2021) Health benefits of fermented bamboo shoots: The twenty-first century green gold of northeast India. Appl Biochem Biotechnol 193: 1800-1802.
    [30] Haghshenas B, Nami Y, Almasi A, et al. (2017) Isolation and characterization of probiotics from dairies. Iran J Microbiol 9: 234-243.
    [31] Abrunhosa L, Inês A, Rodrigues AI, et al. (2014) Biodegradation of ochratoxin A by Pediococcus parvulus isolated from Douro wines. Int J Food Microbiol 188: 45-52.
    [32] Roghmann MC, McGrail L (2006) Novel ways of preventing antibiotic-resistant infections: What might the future hold? Am J Infect Control 34: 469-475.
    [33] Alkalbani NS, Turner MS, Ayyash MM (2019) Isolation, identification, and potential probiotic characterization of isolated lactic acid bacteria and in vitro investigation of cytotoxicity, antioxidant, and antidiabetic activities in fermented sausage. Microb Cell Fact 18: 3-12.
    [34] Pessoa WFB, Melgaco ACC, de Almeida ME, et al. (2017) In vitro activity of Lactobacilli with probiotic potential isolated from cocoa fermentation against Gardnerella vaginalisBiomed Res Int 2017: 1-10.
    [35] Trunk T, Khalil HS, Leo JC (2018) Bacterial autoaggregation. Microbiology 4: 140-164.
    [36] Tuo Y, Yu H, Ai L, et al. (2013) Aggregation and adhesion properties of 22 Lactobacillus strains. J Dairy Sci 96: 4252-4257.
    [37] Kocabay S, Çetinkaya S (2020) Probiotic properties of a Lactobacillus fermentum isolated from new-born faeces. J Oleo Sci 69: 1579-1584.
    [38] Tamang B, Tamang JP (2009) Lactic acid bacteria isolated from indigenous fermented bamboo products of Arunachal Pradesh in India and their functionality. Food Biotechnol 23: 133-147.
    [39] He X, Lux R, Kuramitsu HK, et al. (2009) Achieving probiotic effects via modulating oral microbial ecology. Adv Dent Res 21: 53-56.
    [40] Santos KMO, Vieira ADS, Salles HO, et al. (2015) Safety, beneficial and technological properties of Enterococcus faecium isolated from Brazilian cheeses. Braz J Microbiol 46: 237-249.
    [41] Xiong L, Ni X, Niu L, et al. (2019) Isolation and preliminary screening of a Weissella confusa strain from giant panda (Ailuropoda melanoleuca). Probiotics Antimicrob Proteins 11: 535-544.
    [42] Zeng Y, Li Y, Wu QP, et al. (2020) Evaluation of the antibacterial activity and probiotic potential of Lactobacillus plantarum isolated from Chinese homemade pickles. Can J Infect Dis Med Microbiol 2020: 1-11.
    [43] Powthong P, Suntornthicharoen P (2015) Isolation, identification and analysis of probiotic properties of lactic acid bacteria from selective various traditional Thai fermented food and kefir. Pak J Nutr 14: 67-74.
    [44] Kamboj K, Vasquez A, Balada-Liasat JM (2015) Identification and significance of Weissella species infections. Front Microbiol 6: 1-7.
    [45] Wu Z, Wu B, Li Y, et al. (2021) Identification and safety assessment of Enterococcus thailandicus TC1 isolated from healthy pigs. PLoS One 16: e0254081.
    [46] EgervÄrn M, Danielsen M, Roos F, et al. (2007) Antibiotic susceptibility profiles of Lactobacillus reuteri and Lactobacillus fermentumJ Food Prot 70: 412-418.
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