Effect of probiotic Lactobacillus plantarum Dad-13 powder consumption on the gut microbiota and intestinal health of overweight adults

Mycotoxins are major food contaminants affecting global food security, especially in low and middle-income countries. The European Union (EU) funded project, MycoKey, focuses on “Integrated and innovative key actions for mycotoxin management in the food and feed chains” and the right to safe food through mycotoxin management strategies and regulation, which are fundamental to minimizing the unequal access to safe and sufficient food worldwide. As part of the MycoKey project, a Mycotoxin Charter (charter.mycokey.eu) was launched to share the need for global harmonization of mycotoxin legislation and policies and to minimize human and animal exposure worldwide, with particular attention to less developed countries that lack effective legislation. This document is in response to a demand that has built through previous European Framework Projects—MycoGlobe and MycoRed—in the previous decade to control and reduce mycotoxin contamination worldwide. All suppliers, participants and beneficiaries of the food supply chain, for example, farmers, consumers, stakeholders, researchers, members of civil society and government and so forth, are invited to sign this charter and to support this initiative.

Adhesion capacity is considered one of the selection criteria for probiotic strains. The purpose of this study was to determine the adhesion properties of two candidate probiotics, Lactobacillus plantarum Dad-13 and Lactobacillus plantarum Mut-7. The evaluation included the hydrophobicity of the cell surface using microbial adhesion to hydrocarbons (MATH), autoaggregation, and the adhesion of L. plantarum Dad-13 and L. plantarum Mut-7 to the intestinal mucosa of Sprague Dawley rat, followed by genomic analysis of the two L. plantarum strains. L. plantarum Dad-13 and L. plantarum Mut-7 showed a high surface hydrophobicity (78.9% and 83.5%) and medium autoaggregation ability (40.9% and 57.5%, respectively). The exposure of both isolates to the surface of the rat intestine increased the total number of lactic acid bacteria on the colon compartment, from 2.9 log CFU/cm² to 4.4 log CFU/cm² in L. plantarum Dad-13 treatment and to 3.86 log CFU/cm² in L. plantarum Mut-7 treatment. The results indicate the ability of two L. plantarum to attach to the surface of the rat intestine. The number of indigenous E. coli in the colon also decreased when the compartment was exposed to L. plantarum Dad-13 and Mut-7, from 2.9 log CFU/cm² to 1 log CFU/cm². Genomic analysis revealed that both strains have genes related to adhesion properties that could play an important role in increasing the adherence of probiotics to the intestinal mucosa such as gene encoding fibronectin-binding protein, chaperonin heat shock protein 33 (Hsp33), and genes related to the capsule and cell wall biosynthesis. Based on these findings, we believe that L. plantarum Dad-13 and L. plantarum Mut-7 have adhesion properties to the intestinal mucosa in the rat intestine model system. The present research will be essential to elucidate the molecular mechanism associated with adhesion in our two probiotic strains.

Indonesia is a developing country facing the national problem of the growing obesity and diabetes in its population due to recent drastic dietary and lifestyle changes. To understand the link between the gut microbiome, diet, and health of Indonesian people, fecal microbiomes and metabolomes of 75 Indonesian adults in Yogyakarta City, including obese people (n = 21), type 2 diabetes (T2D) patients (n = 25), and the controls (n = 29) were characterized together with their dietary and medical records. Variations of microbiomes showed a triangular distribution in the principal component analysis, driven by three dominant bacterial genera, namely Bacteroides, Prevotella, and Romboutsia. The Romboutsia-driven microbiome, characterized by low bacterial diversity and high primary bile acids, was associated with fat-driven obesity. The Bacteroides-driven microbiome, which counteracted Prevotella but was associated with Ruminococcaceae concomitantly increased with high-carbohydrate diets, showed positive correlation with T2D indices but negative correlation with body mass index. Notably, Bacteroides fragilis was increased in T2D patients with a decrease in fecal conjugated bile acids, particularly tauroursodeoxycholic acid (TUDCA), a farnesoid X receptor (FXR) antagonist with anti-diabetic activity, while these features disappeared in patients administered metformin. These results indicate that the gut microbiome status of Indonesian adults is differently associated with obesity and T2D under their varied dietary habits.

In the present study, we isolated and screened thirty strains of GABA (γ-aminobutyric acid)-producing lactic acid bacteria (LAB) from traditional Indonesian fermented foods. Two strains were able to convert monosodium glutamate (MSG) to GABA after 24 h of cultivation at 37 °C based on thin layer chromatography (TLC) screening. Proteomic identification and 16S rDNA sequencing using MALDI-TOF MS identified the strain as Lactobacillus plantarum designated as L. plantarum FNCC 260 and FNCC 343. The highest yield of GABA production obtained from the fermentation of L. plantarum FNCC 260 was 809.2 mg/L of culture medium after 60 h of cultivation. The supplementation of 0.6 mM pyridoxal 5’-phosphate (PLP) and 0.1 mM pyridoxine led to the increase in GABA production to 945.3 mg/L and 969.5 mg/L, respectively. The highest GABA production of 1226.5 mg/L of the culture medium was obtained with 100 mM initial concentration of MSG added in the cultivation medium. The open reading frame (ORF) of 1410 bp of the gadB gene from L. plantarum FNCC 260 encodes 469 amino acids with a calculated molecular mass of 53.57 kDa. The production of GABA via enzymatic conversion of monosodium glutamate (MSG) using purified recombinant glutamate decarboxylase (GAD) from L. plantarum FNCC 260 expressed in Escherichia coli was found to be more efficient (5-fold higher within 6 h) than the production obtained from fermentation. L. plantarum FNCC 260 could be of interest for the synthesis of GABA.

Probiotic coffee is an alternative to processed coffee that is preferred and can improve the balance of intestinal microflora so that it has a positive impact on health. Cell viability of probiotics may decrease during storage. Factors that can affect viability during storage are storage temperature, packaging, oxygen, and water activity. This study is aimed at evaluating the viability, storage stability, and shelf life of the probiotic instant coffee Lactiplantibacillus plantarum subsp. plantarum Dad-13 in vacuum and nonvacuum aluminium foil packaging and different storage temperatures. This study used a complete randomised design with three replicates of treatments. They were packaged using 90μm thick aluminium foil in a vacuum and nonvacuum and stored at 4C and 30C for 50 days and 37C for 15 days. Based on the literature, a temperature of 4C can maintain the viability of probiotics for more than one month, the temperature commonly used to store dry products is room temperature (30C), so longer storage (50 days) is tried. Meanwhile, to accelerate the prediction of quality degradation, extreme temperatures were used based on the literature that the viability of probiotics decreased drastically after being stored at 37C for 7 days, then tried for longer storage (15 days). The evaluation of product was carried by sensory testing by comparing commercial instant coffee. The product has been tested for cell viability, water activity, and shelf life. The result showed that the colour attribute was significantly different for all formulations. The bitterness of probiotic instant coffee differed significantly from other formulations. The commercial instant coffee was preferred by panellist in terms of colour and bitterness. The aroma, sweetness, and overall attributes of all formulations were not significantly different. The cell viability in vacuum was higher than nonvacuum treatment, and it was higher in 4C. However, cell viability for all treatments and during storage was still above 10⁷ log CFU/g. Water activity in probiotic instant coffee with vacuum packaging is lower than in nonvacuum and stored at 4C lower than in other temperatures. However, all treatments were still below 0.60. The shelf life of products reaches two years when they are stored in vacuum packaging at 4C while a temperature of 30C reaches 3 months. So, the panellists accepted probiotic instant coffee, vacuum packaging, and low temperature could maintain viability, stability, and longer shelf life.