A preliminary investigation of filamentous actinobacteria isolated from Algerian bee-collected pollen: diversity, characterization, and screening for extracellular enzyme production and antimicrobial activity.
Aug 2026· Folia Microbiologica (Prague)· 0 citations· 55 references
Medicine
TL;DR
It is demonstrated that bee pollen represents a promising source of actinobacterial strains, which have potential antimicrobial and enzymatic activities and provide valuable bioactive compounds for use in medical, food, and agricultural applications.
The integrated experimental and in silico approach highlights soil-derived actinomycetes as versatile and sustainable bioresources with significant pharmaceutical and biotechnological potential, emphasizing their role in combating antimicrobial resistance and enabling the rational development of novel therapeutic and industrial products.
Meghana Arivilu, Shaziya Sulthana, Vijay Ramesh et al.· Journal of Pure and Applied...· 0 citations
Actinobacteria from extreme environments represent a valuable source of novel bioactive secondary metabolites with potential antimicrobial applications. The aim of this study was to isolate, identify, and evaluate the antimicrobial potential of a newly isolated strain of actinobacteria. AHA8 strain, was isolated from an Algerian desert soil sample in the Ahaggar region (Tamanrasset) by the dilution-agar plating method using a chitin-vitamins B medium supplemented with nalidixic acid and actidione. Morphological characterization indicated that this strain belonged to the genus Streptomyces. Phylogenetic analysis based on the 16S rRNA gene showed that the strain is closely related to Streptomyces djakartensis NBRC 15409T (99.57% sequence similarity). Strain AHA8 showed very strong activity against pathogenic staphylococci, including Staphylococcus aureus (MRSA 639c), as well as against other Gram-positive bacteria: Bacillus subtilis (ATCC 663) and Listeria monocytogenes (ATCC 13932). Additionally, the strain exhibited a moderate activity against mycotoxigenic and phytopathogenic fungi, including Aspergillus carbonarius (M333), A. westerdijkiae (ATCC 3174), Fusarium culmorum (Fc), and Umbelopsis ramanniana (NRRL 1829). Almost the same results were observed for Gram-negative bacteria and the pathogenic yeast Candida albicans (M3). Therefore, four solvents (n-hexane, dichloromethane, ethyl acetate, and n-butanol) were used to extract the bioactive secondary metabolites produced by the AHA8 culture on a synthetic starch medium. The highest antibacterial activity was obtained with the butanolic and ethyl acetate extracts. These findings demonstrate that the desert-derived strain AHA8 represents a promising source of antimicrobial secondary metabolites and supports further studies aimed at the purification and characterization of its bioactive compounds.
S. Saadi, Hafsa Yaiche Achour, N. Djemouai et al.· Analele Universitatii din Or...· 0 citations
Aims: The present study aimed to isolate, identify, and evaluate extracellular enzyme-producing bacterial endophytes from the rhizomes of Curcuma caesia Roxb. and to assess their potential for biotechnological applications. Study Design: An experimental, laboratory-based study.
Place and Duration of Study: Department of Biotechnology, Dr B. R. Ambedkar University, Etcherla, Andhra Pradesh, India, from June to May 2025.
Methodology: Endophytic bacteria were isolated from surface-sterilized rhizomes of Curcuma caesia and identified through morphological, biochemical, and 16S rRNA gene sequence analyses. The isolates were screened for extracellular amylase, protease, Cellulase, and lipase production using standard qualitative plate assays. Enzyme activities were quantified using the dinitrosalicylic acid (DNS) assay for amylase and cellulase, the Folin-Ciocalteu method for protease, and the olive oil emulsion titration assay for lipase.
Results: Three bacterial endophytes were identified as Enterobacter hormaechei, Bacillus flexus, and Bacillus amyloliquefaciens. Enterobacter hormaechei exhibited the highest amylase (85 µg/mL; 0.000047 U/mL) and protease (70 µg/mL; 0.000039 U/mL) activities. In contrast, Bacillus amyloliquefaciens showed the highest cellulase (65 µg/mL; 0.000036 U/mL) and lipase (9.67 U/mL) activities, whereas Bacillus flexus displayed moderate enzyme production. The variation in enzyme activity among the isolates indicated their diverse hydrolytic capabilities and functional roles in the degradation of starch, proteins, cellulose, and lipids.
Conclusion: The bacterial endophytes associated with Curcuma caesia possess substantial extracellular enzyme-producing potential. The superior amylase and protease activities of Enterobacter hormaechei and the enhanced cellulase and lipase production by Bacillus amyloliquefaciens indicate their potential for agricultural, industrial, and biotechnological applications. Further studies on enzyme purification, optimisation of production conditions, and large-scale production are recommended to evaluate their commercial potential.
Gujjali Lavanya, S. Ponamgi, Sujatha Peela· Asian journal of microbiolog...· 0 citations
Lactic acid bacteria (LAB) constitute a group of microorganisms of considerable interest in food biotechnology because of their technological properties and their ability to produce a wide range of antimicrobial metabolites. The present study aimed to evaluate the technological profile and antimicrobial potential of LAB isolated from the gut of worker Macrotermes subhyalinus collected in the Lamto region (Toumodi, Côte d’Ivoire). Four strains identified by 16S rRNA gene sequencing were selected: Pediococcus acidilactici KF806466.1, Pediococcus pentosaceus KF806470.1, Lactobacillus brevis KF806467.1, and Lactobacillus plantarum KF806469.1. Their technological properties were assessed by evaluating growth under different pH values, temperatures, and NaCl concentrations, as well as their production of organic acids, acidification capacity, and bacteriocin-producing ability. Antimicrobial activity was determined using the agar well diffusion method against Bacillus subtilis ATCC 6633, Staphylococcus aureus ATCC 25913, and Pseudomonas aeruginosa ATCC 27853. The results showed that all four strains exhibited optimal growth at pH 6.5 and 37 °C and displayed moderate tolerance to NaCl. Chromatographic analyses revealed a diverse production of organic acids, with lactic acid being the predominant metabolite. The Pediococcus strains exhibited the highest acidification capacity and produced substantial amounts of antimicrobial substances. The inhibition zone diameters demonstrated strong antibacterial activity, particularly for P. pentosaceus and L. brevis. These findings suggest that LAB isolated from the gut of M. subhyalinus represents a promising source of biotechnologically valuable strains that could be exploited as protective cultures and biopreservative agents in food systems.
T. Yoro, Katinan Remy Coulibaly, Aya Philomène Kokora et al.· GSC Advanced Research and Re...· 0 citations
Hydrolytic enzymes produced by bacteria have broad potential for substrate degradation and industrial processing. This study isolated, identified, and screened culturable bacteria from common bean (Phaseolus vulgaris L.) rhizospheric soil in Akungba-Akoko for amylase and protease production. Isolates were characterised using cultural, morphological, and biochemical tests, and their identities were determined by comparison with standard bacteriological descriptions. Amylolytic and proteolytic activities were screened on media containing 1% soluble starch or skim milk, respectively. Clear-zone formation indicated a positive reaction, and hydrolytic indices were calculated from the diameters of the clearance zones and colonies. Positive isolates were further evaluated by quantitative enzyme assays using the dinitrosalicylic acid method. Seventeen bacterial isolates representing nine genera were identified. Bacillus megaterium (D40) showed the highest amylolytic index (3.61) and amylase activity (5.45±0.14 U/mL). Pseudomonas sp. (B20) showed the highest proteolytic index (3.38) and protease activity (1.19±0.02 U/mL). Actinobacillus sp. (D42) had the lowest amylolytic index (0.08), whereas Streptococcus sp. (C40) had the lowest proteolytic index (0.29). Several isolates showed no detectable activity for one or both enzymes. The findings demonstrate that bean rhizospheric soil contains culturable bacteria with variable amylolytic and proteolytic potential. These isolates may provide candidate sources for subsequent optimisation and characterisation of microbial enzymes intended for industrial applications.
O. R. Adeoyo· Asian Journal of Biotechnolo...· 0 citations
Common carp (Cyrinus carpio) is a globally important aquaculture species valued for its nutritional quality. This study aimed to isolate intestinal bacteria from the gut of C. carpio, evaluate their probiotic potential, phenotypic characteristics (biochemical tests) and characterize them using molecular techniques. While only one isolate showed the highest pH tolerance, numerous isolates also exhibited strong bile tolerance. Lysozyme tolerance, phenol tolerance, and high autoaggregation ability were recorded in four different isolates. Notably, isolates three isolates showed high cell surface hydrophobicity. Antagonistic activity was demonstrated against Bacillus subtilis and Micrococcus luteus in two isolates, and against Staphylococcus aureus and M. luteus in one isolate. Strong antioxidant activity was observed in three isolates. All isolates were susceptible to neomycin and ofloxacin, but resistant to ampicillin, bacitracin, and carbenicillin. Hemolysis assays revealed α-hemolytic activity in some isolates, while others showed γ-hemolysis. 16S rRNA gene sequence analysis identified that isolate C1-1 as closely related to Klebsiella pneumoniae subsp. rhinoscleromatis, while isolates C4-1, C4-3, and C4-4 were closely related to Klebsiella quasivariicola. MALDI-TOF MS revealed that isolates belonged mainly to the genera Klebsiella, Bacillus, and Enterobacter. The results show that the different isolates exhibit probiotic potential and are therefore promising candidates for in vivo studies and use as feed additives in carp farming.
Fadime Özdemir, Öznur Bilgin, Sevinc Dadosova et al.· AQUATIC SCIENCES AND ENGINEE...· 0 citations