Identification of indigenous Lactobacillus isolated from artisanal Algerian dairy product by 16S rRNA Gene Sequencing and MALDI-TOF Mass Spectrometry

Abstract

El-klila, Jben, Rayeb and Lben are artisanal dairy products typical of the North African region. These products are considered a good source of nutrients and a vector par excellence of indigenous lactic acid bacteria with significant technological and therapeutic potential. In this study, fifty-two Lactobacillus isolates from traditional dairy products (El-Klila, Jben and Rayeb) from the Ain Sefra region (southwestern of Algeria) were identified by phenotypic, genotypic and MALDI-TOF mass spectrometry methods. Phenotypic characterization allowed dividing the isolates into two groups: 7.69% of isolates mesophilic and strict heterofermentative and 92.31% isolates mesophilic and optional heterofermentative. The isolates identification by sequencing 16S rDNA was performed using the universal primers w02 and w18. Comparing the sequences of the isolates with the GenBank database (NCBI) revealed a high percentage with five species of Lactobacillus. Of the 52 isolates, thirteen were identified as Lactobacillus paracasei, four isolates were L. brevis, five isolates were L. rhamnosus and ten isolates were L. plantarum. The lasting twenty isolates were related, at the same time, to the plantarum species and the pentosus species. The use of MALDI-TOF mass spectrometry confirmed the identity of 36 strains of Lactobacillus. Of the 20 isolates related to the plantarum / pentosus group by 16S rDNA, 50% were identified as L. plantarum. Finally, the results of the two combined methods allowed us to correctly identify 80.76% of the Lactobacillus isolates at the genus and species level. The analysis by MALDI-TOF SM has proved to be a very reliable, fast (less than an hour) and inexpensive tool for identifying native Lactobacillus species from artisanal dairy products. This method can constitute a major tool for the study of the microbial biodiversity of artisanal food products.

​Application of MALDI-TOF Mass Spectrometry to Identify Lactic Acid Bacteria Isolated from Artisanal Dairy Products in Algeria

“…Among 116 strains were identified, 11 of them identified with log(score) 2.3, 65 with log(score) 2.3 and 2 and 40 strains with log(score) 2 and 1.7. The values found in our results are different and higher than those of the score values of the strains that were also isolated from some Algerian artisanal dairy products by Arezki et al, (2019) Application of MALDI-TOF Mass Spectrometry to Identify Lactic Acid Bacteria Isolated from Artisanal Dairy Products in Algeria strains had scores higher than 2. On the other hand, the value of Lactobacillus paracasei species is higher than the value found in our strain.…”

“…Meghoufel et al, (2017) reporte the dominance of the genus Enterococcus followed by the two genera Leuconostoc and Lactobacillus in traditional J'ben. Furthermore, the identification of lactic strains isolated from some dairy products by the same technique by Arezki et al, (2019) showed the presence of the genus Lactobacillus. To the best of our kcnowledge there is no much studies about the isolation and identification of LAB from five types « J'ben Smen, l'ben, Raib and Zebda » of Algerian artisanal dairy products collected from several regions by the MALDI-TOF technique.…”

“…For example Lactobacillus curvatus, Lactobacillus diolivorans, Lactococcus lactis and Leuconostoc mesenteroide , Bifidobacterium animalis and Streptococcus thermophilus have been accurately identified in yoghurts and probiotic foods (Angelakis et al, 2011;Tanigawa et al, 2010). While phenotypic and genotypic methods have been applied to identify LAB isolated from Algerian artisanal fermented milk products, little detailed information on their proteomic identification using MALDI-TOF MS is available (Meghoufel et al, 2017); (Arezki et al, 2019) . This work aimed to isolate and to identify LAB from artisanal dairy products collected from different regions in Algeria and to confirm the use of the MALDI-TOF Mass Spectrometry technique as a method for the proteomic identification.…”

Probiotic Properties of Lactic Acid Bacteria Newly Isolated from Algerian Raw Cow’s Milk

“…Raw milk (from cows, goats, buffalos, sheep, camels, and donkeys), as well as human breast milk, are sources of heterogeneous lactic flora, commonly used to isolate new LAB strains with important probiotic potential, which aroused the interest of several research teams around the world [ 1 , 25 , 26 , 27 ]. LABs have a GRAS (Generally Recognized As Safe) status and many probiotic properties, giving them a multitude of opportunities to be used in the food industry [ 28 ].…”

“…The screening of new bacterial strains with probiotic properties is costly and time-consuming. Raw cow’s milk is a potential source of LAB, which is one of the most commonly used bacteria that can provide food and health benefits related to their ability to produce secondary metabolites and functional proteins [ 1 ]. Many LABs are considered probiotics and are targeted by several researchers for their immense genetic, metabolic, and ecological diversity, as they colonize a wide range of habitats and can have different industrial applications [ 2 ].…”