Antibacterial Substance Produced by a Soil Bacteria Isolated From Rhizosphere of Zingiber Officinale

Abstract

Objective: In our previous study, we have found many isolates of bacteria from Zingiber officinale rhizosphere in Magelang, Central Java, Indonesia. J4, one of the isolates, has been found to contain metabolites which have antibacterial activity. The active chemical compound was unidentified. This study aims to identify the molecular formula of the active compound which has potential antibacterial activity.
 Methods: Identification of selected bacteria (J4 isolate) was based on the 16S rRNA gene sequence. Extraction of J4 isolate culture broth was carried out using ethyl acetate and followed by fractionation with hexane, chloroform-methanol (7:3), and methanol. The fraction which has antibacterial activity analyzed using IR Spectroscopy and LC-TOF-MS.
 Results: BLAST analysis result of the 16S rRNA sequence showed that J4 isolate is Burkholderia sp with 99% similarity. According to the IR spectroscopy examination of the active fraction, there were OH, CH, and carbonyl stretching. LC-TOF-MS analysis showed 5 molecular formulas with m/z of 253, 274, 387 (two formulas), and 404 in the active fraction, but there was one formula with no OH groups.
 Conclusion: J4 isolate is a Burkholderia sp. The molecular formula for the antibacterial substance that might be produced by J4 isolate is C6H12N12, C21H29N3O5, C21H26N2O5, C17H22N8O3, and/or C15H35N3O.

Taxonomic and Functional Diversity of Rhizosphere Microbiome Recruited From Compost Synergistically Determined by Plant Species and Compost

“…Previously, several studies have demonstrated that biotic and abiotic factors, such as soil type, plant species and development, and fertilization regimes, played essential roles in the recruitment of rhizosphere microbiome ( George et al, 2017 ; Xu et al, 2017 ). Rhizosphere bacteria may provide first line of defense against pathogens causing soil-borne diseases via several mechanisms such as producing antimicrobial substances ( Sulistyani et al, 2021 ), competing for niches ( Bauer et al, 2018 ), triggering plant immune systems ( Teixeira et al, 2019 ), mineralizing of organic materials ( Richard et al, 2017 ), solubilizing recalcitrant phosphorus, or nitrogen fixation ( Alori et al, 2017 ).…”