Endophytic bacteria associated with Myristica fragrans Houtt: Improved media, bacterial population, preliminary characterization, and potential as antibacterials

Abstract

Abstract. Yunita M, Ohiwal M, Dirks CS, Angkejaya OW, Ilsan NA, Sukmawati S. 2022. Endophytic bacteria associated with Myristica fragrans Houtt: Improved media, bacterial population, preliminary characterization, and potential as antibacterials. Biodiversitas 23: 4047-4054. We have investigated a similar study previously and only obtained 4 isolates that were able to inhibit pathogenic bacteria with a very small inhibition index (1.5 mm-3.4 mm) in NA media. Therefore, the current study was conducted by improving the NA media with the addition of 1% peptone and Myristica fragrans filtrate. The study aimed to evaluate the potential of endophytic bacteria as antibacterials in the modified NA media. Endophytic bacteria were isolated from 5 organs of M. fragrans and were grown on Nutrient Agar added with 1% peptone and M. fragrans filtrate. The total bacterial population was analyzed by the TPC method. Preliminary characterization consisted of macroscopic and microscopic observations. Antibacterial test was carried out by agar diffusion method. The total population of endophytic bacteria varied for all organs of M. fragrans, with the highest population was found in the seeds (1x105 CFU/gr), while the least was found in the pulp (9x103 CFU/gr). A total of 10 isolates were selected and preliminary characterization showed that endophytic bacteria had different macroscopic and microscopic characteristics. All isolates were able to inhibit the growth of Escherichia coli ATCC-27853 and Staphylococcus aureus ATCC-29213 with the largest inhibition zone index was obtained by isolate BJ1 (22.5 mm and 23.8 mm), while the smallest was obtained by isolate TD2 (12.5 mm and 13.6 mm) which were still categorized as strong inhibition. The study concluded that the addition of 1% peptone and M. fragrans filtrate in NA media was able to show far better results compared to our previous study and the strong antibacterials can be developed and formulated in the future.

Antioxidant and antibacterial activities of the rhizome extract of Curcuma zedoaria extracted using some organic solvents

“…The disc method was used to test the antibacterial activity. To determine the activity of each fraction in inhibiting the growth of bacteria, the diameter of the inhibition zone around the disc (which has been treated) was calculated [ 48 ]. The antibacterial test description for three fractions of C. zedoaria can be seen in Table 3…”

Determination of total phenolics, flavonoids, and testing of antioxidant and antibacterial activities of red ginger (Zingiber officinale var. Rubrum)

“…The antibacterial activity test was completed using the disc method. The antibacterial activity of each tested fraction was determined by calculating the clear zone diameter produced around the disc after the test or experiment [ 18 ]. The antibacterial activity test of the three fractions of red ginger can be seen in Table 1 .…”

ISOLASI BAKTERI ENDOFIT BAWANG DAYAK (Eleutherine bulbosa) DAN UJI ANTAGONISME TERHADAP BAKTERI Escherichia coli DAN Staphylococcus aureus

“…Hal ini didukung oleh Gould (2000) yang menyatakan bahwa faktor-faktor yang mempengaruhi kecepatan difusi senyawa antibakteri antara lain jumlah mikroba, kandungan media, temperatur dan waktu inkubasi. Selain itu, diameter zona hambat juga dipengaruhi oleh spesies bakteri dan kemampuan senyawa antibakteri yang dihasilkan oleh masing-masing spesies bakteri (Yunita et al, 2022). Terbentuknya zona hambat kemungkinan karena adanya kontak antara senyawa bioaktif yang dihasilkan oleh bakteri endofit dengan sel bakteri patogen sehingga mempengaruhi sintesis dinding sel dan mengganggu permeabilitas membran sel bakteri patogen (Yunita et al, 2022).…”