Phenotypic and genetic characterization of differential galacto-oligosaccharide utilization in Lactobacillus plantarum

Abstract

Several Lactobacillus plantarum strains are marketed as probiotics for their potential health benefits. Prebiotics, e.g., galacto-oligosaccharides (GOS), have the potential to selectively stimulate the growth of L. plantarum probiotic strains based on their phenotypic diversity in carbohydrate utilization, and thereby enhance their health promoting effects in the host in a strain-specific manner. Previously, we have shown that GOS variably promotes the strain-specific growth of L. plantarum. In this study we investigated this variation by molecular analysis of GOS utilization by L. plantarum. HPAEC-PAD analysis revealed two distinct GOS utilization phenotypes in L. plantarum. Linking these phenotypes to the strain-specific genotypes led to the identification of a lac operon encoding a β-galactosidase (lacA), a permease (lacS), and a divergently oriented regulator (lacR), that are predicted to be involved in the utilization of higher degree of polymerization (DP) constituents present in GOS (specifically DP of 3–4). Mutation of lacA and lacS in L. plantarum NC8 resulted in reduced growth on GOS, and HPAEC analysis confirmed the role of these genes in the import and utilization of higher-DP GOS constituents. Overall, the results enable the design of highly-selective synbiotic combinations of L. plantarum strain-specific probiotics and specific GOS-prebiotic fractions.

Isolation, characterization and comparative genomics of potentially probiotic Lactiplantibacillus plantarum strains from Indian foods

“…In the case of DKL3, all these genes were absent, justifying its inability to utilize lactose. This operon has also been shown to be involved in utilization of galacto-oligosaccharides (GOS) but the absence of lacR has been associated with non-GOS utilization phenotype 56 . Thus, none of our strains might be able to utilize GOS.…”

Dietary calcium phosphate strongly impacts gut microbiome changes elicited by inulin and galacto-oligosaccharides consumption

“…GOS utilization is diverse in Bifidobacterium and a multitude of extra- and intracellular hydrolases and import systems have been attributed to different species and have also shown to be strain specific [ 6 , 65 – 67 ]. Lactobacilli have limited capacity to utilize GOS or inulin and commonly rely on intracellular GOS hydrolysis [ 68 – 70 ], and extracellular digestion of inulin has been described for several species [ 71 – 73 ]. GOS metabolism is often facilitated by ABC transporters and occasionally by lactose permeases in Bifidobacterium species [ 65 , 66 , 74 ], while several Lactobacillus species (i.e., L. acidophilus , L. reuteri and L. plantarum) employ lactose permeases for GOS import [ 68 – 70 ].…”

“…Lactobacilli have limited capacity to utilize GOS or inulin and commonly rely on intracellular GOS hydrolysis [ 68 – 70 ], and extracellular digestion of inulin has been described for several species [ 71 – 73 ]. GOS metabolism is often facilitated by ABC transporters and occasionally by lactose permeases in Bifidobacterium species [ 65 , 66 , 74 ], while several Lactobacillus species (i.e., L. acidophilus , L. reuteri and L. plantarum) employ lactose permeases for GOS import [ 68 – 70 ]. To the best of our knowledge, the mechanisms of GOS or inulin utilization in Faecalibaculum has not been described to date.…”

Evaluation of IR Biotyper for Lactiplantibacillus plantarum Typing and Its Application Potential in Probiotic Preliminary Screening

“…In most cases, the large number of probiotic candidates lead to the use of a “step-by-step approach” involving a series of in vitro required tests to progressively reduce the number of candidate probiotics ( de Melo Pereira et al, 2018 ; Yoha et al, 2021 ). Because the properties and benefits of L. plantarum are strain-specific, an easy-to-use method for fast and effective L. plantarum strain typing is highly desirable in both academia and industry ( Fuhren et al, 2020 ).…”