Diversity, antimicrobial and antioxidant activities of culturable bacterial endophyte communities in Aloe vera

• Published in: FEMS microbiology letters Vol. 362; no. 23; p. fnv184
• Main Authors: Akinsanya, Mushafau Adewale, Goh, Joo Kheng, Lim, Siew Ping, Ting, Adeline Su Yien
• Format: Journal Article
• Language: English
• Published: England Oxford University Press 01.12.2015
• Subjects: Acetic acid; Aloe; Aloe - microbiology; Aloe vera; Anti-Infective Agents - chemistry; Anti-Infective Agents - isolation & purification; Anti-Infective Agents - pharmacology; Antiinfectives and antibacterials; Antioxidants; Ascorbic acid; Bacillus; Bacillus - genetics; Bacillus - isolation & purification; Bacteria; Bacteria - chemistry; Bacteria - classification; Bacteria - genetics; Bacteria - isolation & purification; Bioactive compounds; Biodiversity; Biological activity; Biphenyl Compounds; Candida albicans - drug effects; Chryseobacterium; Communities; E coli; Endophytes; Endophytes - classification; Endophytes - genetics; Endophytes - isolation & purification; Endophytes - physiology; Enterobacter; Ethyl acetate; Free Radical Scavengers - chemistry; Free Radical Scavengers - isolation & purification; Free Radical Scavengers - pharmacology; Klebsiella; Metabolites; Microbial Sensitivity Tests; Microbiology; Phylogeny; Picrates; Plant Leaves - microbiology; Plant Roots - microbiology; Plant Stems - microbiology; Proteus vulgaris; Pseudomonas; Pseudomonas - drug effects; Pseudomonas - genetics; Pseudomonas - isolation & purification; Pseudomonas aeruginosa; RNA, Ribosomal, 16S; Salmonella; Scavenging; Shigella; Staphylococcus aureus - drug effects; Staphylococcus aureus - genetics; Staphylococcus aureus - isolation & purification; 16S ribosomal RNA; diversity; bacterial endophytes
• ISSN: 1574-6968; 0378-1097; 1574-6968
• DOI: 10.1093/femsle/fnv184

Twenty-nine culturable bacterial endophytes were isolated from surface-sterilized tissues (root, stem and leaf) of Aloe vera and molecularly characterized to 13 genera: Pseudomonas, Bacillus, Enterobacter, Pantoea, Chryseobacterium, Sphingobacterium, Aeromonas, Providencia, Cedecea, Klebsiella, Cronobacter, Macrococcus and Shigella. The dominant genera include Bacillus (20.7%), Pseudomonas (20.7%) and Enterobacter (13.8%). The crude and ethyl acetate fractions of the metabolites of six isolates, species of Pseudomonas, Bacillus, Chryseobacterium and Shigella, have broad spectral antimicrobial activities against pathogenic Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus cereus, Salmonella Typhimurium, Proteus vulgaris, Klebsiella pneumoniae, Escherichia coli, Streptococcus pyogenes and Candida albicans, with inhibition zones ranging from 6.0 ± 0.57 to 16.6 ± 0.57 mm. In addition, 80% of the bacterial endophytes produced 1,1-diphenyl-2-picrylhydrazyl (DPPH) with scavenging properties of over 75% when their crude metabolites were compared with ascorbic acid (92%). In conclusion, this study revealed for the first time the endophytic bacteria communities from A. vera (Pseudomonas hibiscicola, Macrococcus caseolyticus, Enterobacter ludwigii, Bacillus anthracis) that produce bioactive compounds with high DPPH scavenging properties (75–88%) and (Bacillus tequilensis, Pseudomonas entomophila, Chryseobacterium indologenes, Bacillus aerophilus) that produce bioactive compounds with antimicrobial activities against bacterial pathogens. Hence, we suggest further investigation and characterization of their bioactive compounds. Twenty-nine species of endophytic bacteria were identified, and some species were found to possess bioactive compounds of antioxidant and antimicrobial potential that inhibit pathogenic Candida albicans and Bacillus cereus.