Biotechnological Characteristics Research Articles

Harnessing microbial potential: Exploiting heavy oil-laden soil microbiota for sustainable production of high-yield rhamnolipids from waste cooking oil

Oil polluted soil microbiota plays an important role in the production of biosurfactants. In comparison to synthetic surfactants, biosurfactants offer unique advantages, such as lower toxicity, biodegradability, selectivity, and effectiveness under unpleasant conditions. Despite these benefits, the widespread use of biosurfactants is limited by enormous production costs. To address this challenge, this study aimed to explore the adoption of waste cooking for rhamnolipids production. Two prominent bacterial strains: Kosakonia cowanni and Acinetobacter colcoaceticus, were obtained from heavy oil-laden soil samples, and further demonstrated their capability for rhamnolipids production from waste cooking oil (Acinetobacter colcoaceticus: 0.51 g/L, Kosakonia cowanii: 0.39 g/L). The biosurfactants obtained were characterized through TLC, FTIR, and H NMR to confirm their rhamnolipid identities as mono-rhamnolipids. The findings in our study emphasizes the potential of cost-effective production of rhamnolipids that possess interesting biotechnological features through the synergy of oil-polluted environments and waste cooking oil. This study contributes significantly to the development of sustainable rhamnolipid production using non-pathogenic strains. By harnessing these microorganisms, we advance towards addressing critical environmental challenges, such as heavy metal contamination in water. This research aligns with broader sustainability goals, including clean water and sanitation.

The genus Eutreptiella (Euglenophyceae/Euglenozoa) across its global distribution range.

The genus Eutreptiella (Euglenophyceae/Euglenozoa) comprises unicellular organisms known for their photosynthetic capacity and significant role in marine ecosystems. This review highlights the taxonomic, ecological, and biotechnological characteristics of Eutreptiella species, emphasizing their morphological and genomic adaptations. Eutreptiella species exhibit high phenotypic plasticity, enabling adaptation to various environmental conditions, from nutrient-rich waters to high-salinity conditions. They play a crucial role in primary production and nutrient cycling in marine ecosystems. Genetic and transcriptomic studies have revealed their complex regulatory mechanisms and potential for biofuel and nutraceutical production. Eutreptiella blooms significantly impact local ecosystems, influencing nutrient availability and community dynamics. Additionally, interactions with associated bacteria enhance their growth and metabolic capabilities. The genus shows substantial genetic variability, suggesting potential misidentifications or a polyphyletic nature. Further comprehensive studies are needed to clarify their taxonomy and evolutionary relationships. Understanding and managing Eutreptiella populations is essential to leverage their biotechnological potential and ensure the health of marine ecosystems.

Modeling of the conditions of the process of biotransformation of fish raw materials by bacterial starter cultures

Abstract In food biotechnology, special attention is given to the biotransformation by promising strains of bacterial starter cultures to obtain food products with improved quality characteristics and functional properties. Biotransformation using bacterial starter cultures may be a means to increase the shelf life of fish products, enhance their organoleptic properties, and increase their nutritional value through the formation of metabolites of their activity, which are the main factors of bioconservation and synthesis of vitamins and other biologically active substances. The probiotic properties of bacterial starter cultures will significantly influence the optimization of the indigenous microflora of the gastrointestinal tract, thereby strengthening the human body and its immune system overall to maintain a healthy lifestyle. The development of this trend is associated with the interest of the Russian population in products with a probiotic focus. In this regard, an analysis of data on the justification of the use of bacterial starter cultures for the biotransformation of fish raw materials has been conducted, and the necessary bacterial starter cultures have been selected. Based on theoretical and practical foundations, mathematical models of the biotransformation process by bacterial starter cultures have been constructed depending on the properties of fish raw materials and the biotechnological characteristics of the introduced microorganisms. The conducted research has been used to develop subsequent technological regimes for the biotransformation of fish raw materials by bacterial starter cultures as the basis for the formulations of “fast food” products containing functional components, which is justified by the accelerated pace of life and the desire of modern society to monitor their diet by consuming products that support a healthy lifestyle.

Pseudomonas environmental strain produces a DegQ-derived and PDZ domain containing peptide with protease activity.

In the search of new enzymatic activities with a possible industrial application, we focused on those microorganisms and their molecular mechanisms that allow them to succeed in the environment, particularly in the proteolytic activity and its central role in the microorganisms' successful permanence. The use of highly active serine proteases for industrial applications is a modern need, especially for the formulation of detergents, protein processing, and hair removal from animal skins. This report provides the isolation and identification of a highly proteolytic fragment derived from DegQ produced by a Pseudomonas fluorescens environmental strain isolated from a frog carcass. Zymograms demonstrate that a 10kDa protein mainly generates the total proteolytic activity of this strain, which is enhanced by the detergent SDS. Mass spectroscopy analysis revealed that the protein derived a couple of peptides, the ones showing the highest coverage belonging to DegQ. Interestingly, this small protein fragment contains a PDZ domain but no obvious residues indicating that it is a protease. Protein model analysis shows that this fragment corresponds to the main PDZ domain from DegQ, and its unique sequence and structure render a proteolytic peptide. The results presented here indicate that a novel DegQ fragment is sufficient for obtaining high protease activity highlighting that the analysis of environmental microorganisms can render new strains or enzymes with helpful biotechnological characteristics.

Acidophilic bacteria for metal extraction: biotechnological characteristics and applications

Acidophilic bacteria for metal extraction: biotechnological characteristics and applications

Assessment of Potential Probiotic Properties and Biotechnological Activities of Lactobacillus Strains Isolated from Traditional Algerian Fermented Wheat ELHAMOUM

Background: The objective of the current study was to explore the in vitro probiotic and technological characteristics of lactic acid bacteria (LAB) isolated from Algerian fermented wheat. Methods: Three LAB strains were selected and identified using 16S rRNA gene sequencing, in vitro assessments of probiotic properties included resistance to simulated gastric and intestinal conditions, auto-aggregation and antimicrobial susceptibility against common pathogens. Furthermore, the strains were evaluated for their biotechnological properties. Results: The results of 16S rRNA gene sequencing showed that two of them were Levilactobacillus brevis (LAn91 and LAn110) and LAn12a was Lactiplantibacillus pentosus. The tolerance of all strains to gastric acid and bile salts was more than 90%; they showed a high auto-aggregation capacity and a variable antagonistic property against pathogenic strains. Strain LAn12a presented the best biotechnological characteristics (proteolytic, acidifying and lactose hydrolysis), while the LAn91 and LAn110 strains were not able to acidify milk. All the strains exhibited a survival count in fermented milk exceeding 7 log CFU/ml during storage at 4°C on day 21, which surpasses the requirement of 6 log CFU/ml to provide health benefits. These bacteria can also be employed for the creation of functional foods and to validate their suitability as probiotic starter cultures.

Dissecting the Genetic Basis of the Technological, Functional, and Safety Characteristics of Lacticaseibacillus paracasei SRX10.

Nonstarter lactic acid bacteria (NSLAB) are major contributors to the unique characteristics (e.g., aroma, flavor, texture) of dairy and nondairy fermented products. Lc. paracasei SRX10 is an NSLAB strain originally isolated from a traditional Greek cheese and previously shown to exhibit favorable biotechnological characteristics. More specifically, the strain showed tolerance to simulated gastrointestinal conditions, exopolysaccharide (EPS) biosynthetic capacity, and lack of hemolytic activity and was used in the production of yoghurt and feta cheese with distinct organoleptic characteristics. The aim of the present study was to investigate these traits at the genome level through whole-genome sequencing (WGS), annotation, and comparative genomics. Functional annotation of the genome revealed that Lc. paracasei SRX10 can utilize different carbon sources, leading to the generation of flavor compounds, including lactic acid, acetate, ethanol, and acetoin. Similarly, full clusters for fatty acid biosynthesis, protein and peptide degradation, as well as genes related to survival under extreme temperatures, osmotic shock, and oxidative stress were annotated. Importantly, no transferable antibiotic resistance genes or virulence factors were identified. Finally, strain-specific primers based on genome-wide polymorphisms were designed for the efficient and rapid identification of Lc. paracasei SRX10 via multiplex PCR in fermented products.

Genome-resolved metagenomic analysis of Great Amazon Reef System sponge-associated Latescibacterota bacteria and their potential contributions to the host sponge and reef

The Great Amazon Reef System (GARS) is an extensive biogenic reef influenced by a plume layer of sediments. This creates an extreme environment where light is reduced, thus affecting physicochemical properties as well as living organisms such as sponges and their microbiomes. The sponge’s microbiome has numerous ecological roles, like participation in biogeochemical cycles and host nutrition, helping the sponge thrive and contributing to the ecosystem. Also, sponges and sponge-associated microorganisms are rich sources of bioactive compounds, and their products are applied in different areas, including textile, pharmaceutical, and food industries. In this context, metagenome-assembled genomes (MAG), obtained from GARS sponges microbiota, were analyzed to predict their ecological function and were prospected for biotechnological features. Thus, in this work, tissues of GARS sponges were collected, their metagenomes were sequenced and assembled, and 1,054 MAGs were recovered. Ten of those MAGs were selected based on their taxonomic classification in the candidate phylum Latescibacterota and this group’s abundance in GARS sponges. The workflow consisted of MAG’s quality definition, taxonomic classification, metabolic reconstruction, and search for bioactive compounds. Metabolic reconstruction from medium to high-quality MAGs revealed genes related to degradation and synthesis pathways, indicating functions that may be performed by GARS sponge-associated Latescibacterota. Heterotrophy, a recurring attribute in Latescibacterota that might be crucial for GARS sponge holobiont nutrition, was verified by the presence of genes related to respiration and fermentation. Also, the analyzed bacteria may contribute to the host’s survival in multiple ways, including host protection via defense systems; aid in nutrient consumption by breaking complex substrates and producing essential nutrients like vitamins and certain amino acids; and detoxification of mercury, arsenic, ammonia, and hydrogen sulfide. Additionally, genes linked to persistent organic pollutant degradation, including glyphosate, and biogeochemical cycles reactions, such as ammonification, sulfate reduction, thiosulfate disproportionation, phosphorus remineralization, and complex organic matter degradation, were identified, suggesting the participation of these Latescibacterota in bioremediation and nutrient cycling. Finally, the investigated MAGs contain genes for numerous bioactive compounds, including industrial enzymes, secondary metabolites, and biologically active peptides, which may have biotechnological value.

Biotechnological Features of a Functional Non-Dairy Mixed Juice Fermented with Lacticaseibacillus paracasei SP5

In the present study, a wild-type Lacticaseibacillus paracasei SP5 (L. paracasei SP5) potential probiotic strain (previously isolated from kefir grains) was applied for the 1-day fermentation of an apple–orange–carrot mixed juice. After the fermentation, the mixed juice was refrigerated in cold storage at 4 °C, and the microbiological stability, characterization of volatiles, physicochemical properties (pH, total titratable acidity (TTA), residual sugar content and organic acids content), the sensorial validation (aroma, taste and overall acceptability) of the juice, and the viability of the potential probiotic strain were analyzed. The stored juice exhibited zero colonies of yeasts/fungi and simultaneously the viability of L. paracasei SP5 was retained to 8.28 Log CFU/mL, even after the 4th week of cold storage. The pH values ranged from 3.80 to 3.35 and the TTA values ranged from 0.1344% to 0.1844% lactic acid for the unfermented juice up until the 4th week of cold storage. Furthermore, the organic acids content consisted mostly of lactic acid (4.6 to 9.1 g/L), while malic acid (3.7 to 1.5 g/L), acetic acid (0.6 g/L) and propionic acid (0.3 g/L) were detected only after the 4th week of cold storage. Residual sugar content ranged from the initial value of 122.2 g/L and 106.6 g/L at the end of cold storage. As far as the volatiles’ characterization is concerned: 9 esters, 2 organic acids, 12 alcohols, 3 aldehydes, 1 ketone, 6 terpenes and 4 sesquiterpenes (37 in total) were detected in the unfermented mixed juice and 33 compounds in the fermented juice after 4 weeks of cold storage. The sensorial properties (aroma, taste and overall acceptability) of the fermented mixed juice samples were positively influenced. Consequently, L. paracasei SP5 potential probiotic strain may be applied for the production of probiotic mixed juices, with satisfying viability, volatile profile and organoleptic results.

Comparative analysis of the content of salicylic acid in biotechnological cotton genotypes under some kinds of abiotic stress

The relevance of this study is conditioned by the current findings on salicylic acid (SA) synthesis in plants, which suggest that the presence of some transient factors in cotton is a signal that the stress-protective functions of the plant are being activated. An increase in the content of key mediators of the defence signalling system in cotton cells triggers the activation of stress factors, triggering the defence mechanisms of the living organism. Thus, the resistance of plants to certain types of abiotic stress is achieved by activating the protective reactions of the signalling system. This process allows for the targeted use of biologically active substances such as salicylic acid. Therefore, the purpose of this study is to investigate the combined properties of the protective signalling system of some genetic types of cotton plants, when phenolic acids are synthesised in them. The leading approach to the study of this issue is a laboratory experiment, which allowed comprehensively considering cotton lines containing RNA sensitive to certain types of abiotic stress. Additional biological and chemical techniques were used as auxiliary methods in the field to test the specific effects of saline soils on cotton RNA salicylic acid concentration. This study presents data on the resistance of the RNA interference (RNAi) genotype ESKIMO1 to salinity and limited irrigation. The content of salicylic acid in cotton tissues under the influence of various concentrations of NaCl was studied. The formation of reactive oxygen species in the process of activation of plant defence reactions to certain types of abiotic stress is substantiated. The study materials are of practical value to microbiologists, geneticists, and agronomists. The investigation of the biotechnological features of the plant genotype plays an important role in understanding plant adaptation to natural conditions caused by certain types of abiotic stress. The affordability of salicylic acid allows its widespread application as a commercial reagent in crop production practices

Teaching reform and practice of 'Production Internship' course for biotechnology specialty from the perspective of training application-oriented talents

Production internship is an important teaching tache for undergraduate students to carry out engineering training by using professional skills, and it is a key starting point for fostering application-oriented talents in biotechnology. The Course Group of 'production internship of biotechnology majors' of Binzhou University is investigating application-oriented transformation for local regular colleges and universities, as well as fostering high-level application-oriented talents. By taking green fluorescent protein (GFP) polyclonal antibody as an example, the reform and practice on teaching content, teaching mode, assessment method, continuous improvement of curriculum were carried out. Moreover, the characteristics of the Yellow River Delta-Binzhou Biotechnology & Pharmaceutical Industrial Cluster were taken into account to intensify academic-enterprise cooperation. On one hand, this Course Group designed and rearranged the course contents, carried out essential training through online resources and platforms such as virtual simulation, and recorded, tracked and monitored the progress of production internship through practical testing and software platforms like 'Alumni State'. On the other hand, this Course Group established a practice-and application-oriented assessment method in the process of production internship and a dual evaluation model for continuous improvement. These reform and practices have promoted the training of application-oriented talents in biotechnology, and may serve as a reference for similar courses.

First insights into the gut microbiome of Diatraea saccharalis: From a sugarcane pest to a reservoir of new bacteria with biotechnological potential

A country’s biodiversity is a key resource for the development of a sustainable bioeconomy. However, often the most biodiverse countries on the planet hardly profit from their biological diversity. On the contrary, occasionally components of that biodiversity become a threat to society and its food sustainability. That is the case of the sugarcane borer Diatraea saccharalis. Here, the analysis of the bacteria associated with the digestive tract of D. saccharalis reveals a rich and diverse microbiota. Two types of diets were analyzed under laboratory conditions. The metataxonomic analysis revealed a number of taxa common to most of the larval pools analyzed with relative abundances exceeding 5%, and five families of bacteria which have also been reported in the gut of another Lepidoptera. A large fraction of microorganisms detected by amplicon sequencing were considered to be rare and difficult to cultivate. However, among the cultivable microorganisms, 12 strains with relevant biotechnological features were identified. The strain that showed the highest cellulolytic activity (GCEP-101) was genome sequenced. The analysis of the GCEP-101 complete genome revealed that the values of 16S rRNA identity, the Average Nucleotide Identity, and the digital DNA–DNA hybridization place the strain as a candidate for a new species within the genus Pseudomonas. Moreover, the genome annotation of the putative new species evidenced the presence of genes associated with cellulose degradation, revealing the hidden potential of the pest as a reservoir of biotechnologically relevant microorganisms.

Molecular and biotechnological characteristics of proteolytic activity from Streptococcus thermophilus as a proteolytic lactic acid bacteria to enhance protein-derived bioactive peptides.

The demand for healthy food items with a high nutrient value of bioavailability and bioaccessibility has created a need for continuous development of technology and food ingredients like bioactive peptides. This study aimed to investigate seven proteolytic lactic acid bacteria (PLABs) isolated from the plaa-som (fermented fish) sample originated from silver BARB species for production of proteolytic enzymes. Proteolytic enzymes produced by (PLABs) were used further to create potent bioactive peptides by hydrolyzing proteins throughout PLAB-probiotics enhancer. Protein derived-bioactive peptides was tested the proteolytic activity on different protein sources and examined bioactivities including antioxidative and antimicrobial effect for further use in functional foods. Results of screened-PLAB strains showed high proteolytic activity namely Streptococcus thermophilus strains (KKUPA22 and KKUPK13). These strains have proteolytic system consisting of extracellular and cell-bound enzymes that used for degrading protein in fish flesh protein (FFP) and skim milk (SKM) broth media. Proteolytic activity of tested bacterial enzymes was estimated after incubation at 45, 37, and 50 °C. Furthermore, FFP hydrolysates were formed with various peptides and has small molecular weights (checked by SDS-PAGE) in the range of10.5 to 22 kDa), exhibiting strong activity. Data revealed that S. thermophilus strains (KKUPA22 and KKUPK13) had high antioxidant activity in term of 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2-azinobis-(3-ethylbenzothiazoline-6-sulfonate) (ABTS) radical-scavenging inhibition, and ferric reducing antioxidant power (FRAP) reducing power capacity. Both strains (KKUPA22 and KKUPK13) of S. thermophilus have higher antimicrobial activity against Gram-negative bacteria than against Gram-positive bacteria. We have confirmed presence of proteolytic (prt) gene regions in S. thermophilus strains using specific primers via PCR amplification. Results showed highest homology (100%) with the prtS gene of S. thermophillus located on the cell envelope proteolytic enzymes (CEPEs) such as serine proteinase. Therefore, it concluded that the proteolytic system of tested PLAB strains able to generate bioactive peptides-derived proteins having active biological property, good mechanism of degradability, and bioaccessibility for further use in catalyzing protein of functional foods.

Identification and Technological Characterisation of Lactic Acid Bacteria Iso-lated From Traditional Algerian Cheese “J ben”

Lactic acid bacteria have long been utilized in fermented foods and dairy products such as cheese, these bacteria play an important role in food bio-preservation, organoleptic properties development, and quality improvement. The purpose of this research was to determine and assess the biotechnological characteristics of lactic acid bacteria isolated from traditional Algerian cheese "J'ben". Fifteen lactic acid bacteria (gram positive, catalase negative) were molecularly identified according to their 16S rDNA sequences, six belonged to Enterococcus durans, three to Enterococcus faecium, three to Lactococcus lactis, and three to Leuconostoc mesenteroide. The strains were evaluated for proteolysis, lipolysis, antibacterial activity, exopolysaccharide synthesis, and safety (hemolytic activity). All studied strains had considerable proteolytic activity but no lipolysis potential, they were also all γ-hemolytic. The antimicrobial activity of the stains against three pathogenic bacteria (Staphylococcus warneri, Serratia plymuthica, and Enterobacter aerogenes) revealed that they were active against at least one of them. Finally, only three organisms produced exopolysaccharide in our study Enterococcus durans (KC1); Leuconos-toc mesenteroide (KC6); and Lactococcus lactis (KC15). These findings suggest that the lactic acid bacteria isolated from traditional cheese "J'ben" have significant technological propereties, making them suitable for use as starter culture in fermented dairy products.

Development of Sets-Based Booklets to Improve Critical Thinking Skills and the Effectiveness of Biotechnology Learning in SMA/MA


 Characteristics of learning biotechnology is the existence of a process and product related to everyday life. Therefore, an effective learning process is needed and supported by relevant learning resources. This study aims to analyze the validity of SETS-based biotechnology material booklets used in biotechnology learning. Describe the characteristics of SETS-based biotechnology material booklets. Analyzing students' critical thinking skills in biotechnology learning using SETS-based booklets. Analyzing the effectiveness of biotechnology learning using a SETS-based booklet This research is a research and development (R&D) study. The booklet development trial was conducted in 4 schools, with the research subjects being class XII students in each school. Applicative and meaningful learning of biotechnology can be achieved, one of which is by learning using the SETS vision booklet. The SETS vision booklet contains more concise material, accompanied by attractive, colorful pictures that can effectively improve student learning outcomes. The N-gain value obtained is 0.3-0.4 with the medium category and classical completeness reaching 60%. Critical thinking skills that are formed through active learning using SETS vision booklets are 71% -80% in the high category. Critical thinking skills in integrating SETS elements in biotechnology learning can make it easier for students to understand knowledge concepts, so that they can increase learning effectiveness, namely improving learning outcomes and classical mastery.

Surface Layer Protein Pattern of Levilactobacillus brevis Strains Investigated by Proteomics.

The outermost constituent of many bacterial cells is represented by an S-layer, i.e., a semiporous lattice-like layer composed of self-assembling protein subunits called S-layer proteins (Slps). These proteins are involved in several processes, such as protecting against environmental stresses, mediating bacterial adhesion to host cells, and modulating gut immune response. Slps may also act as a scaffold for the external display of additional cell surface proteins also named S-layer associated proteins (SLAPs). Levilactobacillus brevis is an S-layer forming lactic acid bacterium present in many different environments, such as sourdough, milk, cheese, and the intestinal tract of humans and animals. This microorganism exhibits probiotic features including the inhibition of bacterial infection and the improvement of human immune function. The potential role of Slps in its probiotic and biotechnological features was documented. A shotgun proteomic approach was applied to identify in a single experiment both the Slps and the SLAPs pattern of five different L. brevis strains isolated from traditional sourdoughs of the Southern Italian region. This study reveals that these closely related strains expressed a specific pattern of surface proteins, possibly affecting their peculiar properties.

Microencapsulation of epiphytic coffee yeasts by spray drying using different wall materials: Implementation in coffee medium

The storage of microorganisms in liquid form is the main drawback of commercializing epiphytic coffee yeasts. This work aimed to evaluate the fermentative performance of microencapsulated yeasts by spray drying in a coffee peel and pulp media (CPM). The yeasts, Saccharomyces cerevisiae CCMA 0543, Torulaspora delbrueckii CCMA 0684, and Meyerozyma caribbica CCMA 1738, were microencapsulated using maltodextrin DE10 (MD), high maltose (MA), and whey powder (WP) as wall materials. A Central Composite Rotational Design (CCRD) was used to investigate the effect of operating parameters on the microcapsules' cell viability, drying yield, and water activity. Yeasts reached cell viability and drying yields above 90 and 50 %, respectively. WP maintained the cell viability of the three yeasts over 90 days of storage at room temperature (25 °C) and was selected as a wall material for the three yeasts. M. caribbica showed to be more sensitive to spray drying and less resistant to storage. Some differences were found in the fermentation of the CPM medium, but the microencapsulated yeasts maintained their biotechnological characteristics. Therefore, the microencapsulation of epiphytic coffee yeasts by spray drying was promising to be used in the coffee fermentation process.

Use of yacon in the technology of bread of graded wheat flour

Expanding the range of raw ingredients with high concentration of nutrients that are deficient in the diets of the population is in line with modern trends in the field of healthy nutrition. These raw materials include yacon, which is known for its high inulin content, which, during storage or hydrolytic cleavage, is converted to fructose and other compounds in the form of fructans. The rationale for the choice of recipe composition of bread from graded wheat flour with the addition of yacon powder was carried out according to the results of studying the dynamics of the biotechnological characteristics of the dough and the quality of finished products. As it was shown by the results of the study, the introduction of 3.5% by weight of flour of powdered semi-finished product from yacon into the recipe composition improves the texture, taste, and aroma of bread made from graded wheat flour. 7% addition equates the sample to the control in terms of the structure of porosity, volume and shape, but darkens the crumb and makes the color of the crust more pronounced. 10.5% addition of yacon powder leads to the decrease in the sensory perception of bread

Probiotic and Antifungal Attributes of Lactic Acid Bacteria Isolates from Naturally Fermented Brazilian Table Olives

Research with fermented olives as a source of wild Lactic Acid Bacteria (LAB) strains with probiotic and biotechnological characteristics constitutes a promising field of work. The present study evaluated in vitro probiotic, antifungal, and antimycotoxigenic potential of LAB isolates from naturally fermented Brazilian table olives. Among fourteen LAB isolates, the Levilactobacillus brevis CCMA 1762, Lactiplantibacillus pentosus CCMA 1768, and Lacticaseibacillus paracasei subsp. paracasei CCMA 1770 showed potential probiotic and antifungal properties. The isolates showed resistance to pH 2.0 (survival ≥ 84.55), bile salts (survival ≥ 99.44), and gastrointestinal tract conditions (survival ≥ 57.84%); hydrophobic cell surface (≥27%); auto-aggregation (≥81.38%); coaggregation with Escherichia coli INCQS 00181 (≥33.97%) and Salmonella Enteritidis ATCC 564 (≥53.84%); adhesion to the epithelial cell line Caco-2 (≥5.04%); antimicrobial activity against the bacteria S. Enteritidis ATCC 564 (≥6 mm), Listeria monocytogenes ATCC 19117 (≥6 mm), Staphylococcus aureus ATCC 8702 (≥3 mm), and the fungi Penicillium nordicum MUM 08.16 (inhibition ≥ 64.8%). In addition, the strains showed the ability to adsorb the mycotoxins aflatoxin B1 (≥40%) and ochratoxin A (≥34%). These results indicate that LAB strains from naturally fermented Brazilian table olives are potentially probiotic and antifungal candidates that can be used for food biopreservation.

Microbiological diversity and biotechnological characteristics of the dominant indigenous lactic microflora in Algerian traditional butter (Dhan)

Traditional butter is widely used in pastoral populations in Algeria, thanks to its nutritional value. Several studies have investigated traditional butter produced in Algeria, our study is a contribution to its improvement and valorisation through the phenotypic identification and characterization of lactic acid bacteria responsible for the fermentation of this product. The samples were collected in the regions of Relizane, Oran, Sidi Bel-Abbes and Tindouf. Physicochemical tests make it possible to specify the quality of traditional butter; the pH is 4.5 ± 0.02 to 5.31 ± 0.2, the fat content is 73 ± 0.2 to 83 ± 0.1%, the acid index is 28.05 ± 0.2 to 44.88 ± 0.2 mg KOH.g-1 and the saponification index is 131.85 ± 0.2 to 359.10 ± 0.2 mg KOHg.-1. The microbiological analysis results show that the lactic microflora isolated from butter consists mainly of different genera; Lactobacillus 49%, Lactococcus 20%, Leuconostoc 15%, Enterococcus 11% and Pediococcus 5%. Species identification is based on classical phenotypic characterization; Lb. plantarum 7 isolates (26%), Lb. casei subsp. casei 6 isolates (22%), Lb. casei subsp. rhamnosus and Lb. delbrueckii subsp. bulgaricus 5 isolates (19%), Lb. delbrueckii subsp. delbrueckii 4 isolates (14%), Lc. lactis subsp. cremoris 6 isolates (55%), Lc. lactis subsp. lactis 5 isolates (45%), Ln. mesenteroides subsp. dextranicum 5 isolates (62%), Ln. mesenteroides subsp. mesenteroides 3 isolates (38%), E. faecalis 4 isolates (67%), E. faecium 2 isolates (33%), P. acidilactici3 isolates (100%). They have considerable biotechnological characteristics which allow the constitution of specific starters in the manufacture of Algerian traditional butter.