1.Identification and characterization of lactic acid bacteria isolated from fruit tree rhizosphere in MARDI, Malaysia
Nurul Ain Abu Bakar ; Mohammad Hariz Abdul Rahman ; Nur Alyani Shakri
Malaysian Journal of Microbiology 2017;13(1):xx-xx
Aims: Lactic acid bacteria (LAB) have promising applications in the biotechnology industry. As their diversity in soil is
largely unexplored, a study was undertaken to collect LAB from the soil, and to characterize the isolates.
Methodology and results: Soil samples from around various fruit trees in MARDI were collected for LAB isolation by
accumulation/incubation method. The isolates were examined for their morphological and biochemical characteristics,
and their 16S rDNA sequences. Morphological and biochemical analysis showed that all isolates are gram positive with
different characteristic for each isolates. Further identification were performed and soil samples was found to contain
diverse genera and species of LAB, including Lactobacillus sp. and Bacillus sp. Selected isolates were tested for
resistance against six antibiotics using agar dilution method. Widespread antibiotic resistance among the strains tested
was found towards ampicillin, kanamycin, rifampicin and penicillin.
Conclusion, significance and impact study: LAB have the ability in producing acid and antimicrobial compound which
are useful in various industry. Fastidious characteristics of LAB are among the limitations and challenges in industrial
applications. Diversity of lactic acid-producing bacteria was encountered in the soil which may be useful and have
different characteristics from LAB isolates elsewhere.
Lactic Acid
2.Chemical composition and antimicrobial activities of wood vinegars from carambola, coconut shells and mango against selected plant pathogenic microorganisms
Nur Adliza Baharom ; Mohammad Hariz Abdul Rahman ; Mohammad Shahid Shahrun ; Farah Huda Sjafni Suherman ; Siti Nur Hafizah Masdar
Malaysian Journal of Microbiology 2020;16(6):438-445
Aims:
This work aimed to evaluate the antimicrobial activities of three different sources of wood vinegars obtained from
pyrolysis of carambola (Averrhoa carambola), coconut shells (Cocos nucifera) and mango (Mangifera indica) and to
identify their chemical composition.
Methodology and results:
Agar well diffusion technique was employed to assay the antifungal activity of the wood
vinegars against Fusarium oxysporum, Colletotrichum gleosporoides, and Pestalotiopsis microspora and disc diffusion
technique for antibacterial screening against Ralstonia solanacearum. The chemical compositions of these wood
vinegars were also analyzed using GC-MS by employing the headspace technique. All wood vinegars exhibited
antimicrobial activity against tested pathogens. Wood vinegar from carambola exhibited the most promising antimicrobial
effect followed by coconut shells and mango. The GC-MS analysis revealed the wood vinegars from coconut shells,
carambola, and mango are different in the chemical composition and active compounds. Major compounds identified in
coconut shells are furfural, phenol, benzofuran, acetic acid, hexanal, ethanone, and formic acid. In carambola, the main
compounds are furfural, imidazole, 3-pyridinecarboxaldehyde, benzaldehyde, phenol, benzofuran, indene, acetic acid,
indazole, naphthalene, cyclohexanecarboxylic acid, palmitamide, palmitic acid, heptadecanenitril, and sterylamide.
Meanwhile, the main chemical compounds in the pruning of mango-based vinegar consist of toluene, furfural, imidazole,
annulene, benzaldehyde, phenol, carbamic acid, acetic acid, naphthalene, heptadecanenitril, and stearylamide.
Conclusion, significance and impact of study
It is suggested that wood vinegar from carambola, coconut shells, and
mango is a promising antimicrobial agent in plant disease control, showing good potential for inhibition of selected plant
pathogenic microorganisms.
Anti-Infective Agents
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Acetates