Preliminary Detection of Antibacterial Activity of Fishpond Water Bacteria against Aquaculture Pathogenic Bacteria

Aquaculture is currently experiencing massive loss due to the outbreak of pathogenic bacteria. One of the outbreak causes is the development of pathogenic bacterial resistance to the antibacterial. The problem can be solved using microorganisms that can produce new antibacterial compounds. The purpose of this research was to obtain bacteria from fishpond water that could produce antibacterial compounds. About two out of 81 isolates could produce antibacterial compounds. Those two isolates were obtained from saltwater fishponds in North Jakarta (TS2) and Harapan Island (PHY). All fishpond water was grown in marine broth or Luria broth. Extraction of antibacterial compounds was performed using four types of solvents: chloroform, dichloromethane, ethyl acetate, and methanol. Each of the solvents showed a different result. The extraction can only be successfully performed using chloroform and dichloromethane. Extraction using dichloromethane showed a larger inhibitory clear zone than chloroform. Based on 16S rRNA gene sequencing, PHY isolate was identified as Bacillus sp. and TS2 as Acinetobacter sp. In conclusion, isolate TS2 and PHY, which produced antibacterial compounds, showed potential use as aquaculture probiotics.

Deteksi bakteri pembentuk amina biogenik pada ikan Scombridae secara multiplex PCR

Amina biogenik merupakan komponen basa nitrogen yang terbentuk oleh dekarboksilasi asam amino. Amina biogenik yang sering terdeteksi pada produk perikanan di antaranya histamin, tiramin dan kadaverin. Gen pengkode dekarboksilasi asam amino tersebut yaitu histidine decarboxylase (hdc), tyrosine decarboxylase (tdc) serta lysine decarboxylase (ldc). Penelitian ini bertujuan untuk mendapatkan isolat DNA bakteri beserta konsentrasi dan kemurniannya, menyeleksi media pertumbuhan bakteri, mendeteksi gen hdc, tdc dan ldc menggunakan multiplex PCR serta identifikasi bakteri.. Sampel yang digunakan yaitu ikan tuna beku, tongkol beku, cakalang beku, tuna loin, pindang tongkol potong dan pindang tongkol bumbu kuning serta kontrol positif menggunakan ikan tuna yang disimpan pada suhu ruang selama 3 hari. Penelitian terdiri dari tahap pra-pengayaan bakteri pada media marine broth dan lactose broth, isolasi DNA sampel tanpa dan hasil pra-pengayaan, uji kemurnian dan konsentrasi isolat serta amplifikasi gen target hdc, tdc, ldc menggunakan multiplex PCR. Hasil yang diperoleh yaitu kualitas isolat DNA bakteri pada umumnya sudah murni, dengan konsentrasi isolat 15,75-157,84 ng/µL. Teknik multiplex PCR berhasil mendeteksi gen hdc, tdc dan ldc pada ikan scombridae. Kondisi optimum amplifikasi PCR yaitu annealing pada suhu 50°C selama 90 detik. Gen yang terdeteksi pada sampel tanpa pra-pengayaan yaitu tdc, sedangkan ldc dan hdc ditemukan pada sampel hasil pra-pengayaan media lactose broth dan marine broth. Bakteri pembentuk amina biogenik teridentifikasi sebagai Enterococcus fecalis, M. morganii, E. aerogenes, Citrobacter sp., Hafnia paralvei dan Obesumbacterium proteus. Amina biogenik merupakan komponen basa nitrogen yang terbentuk oleh dekarboksilasi asam amino. Amina biogenik yang sering terdeteksi pada produk perikanan di antaranya histamin, tiramin dan kadaverin. Gen pengkode dekarboksilasi asam amino tersebut yaitu histidine decarboxylase (hdc), tyrosine decarboxylase (tdc) serta lysine decarboxylase (ldc). Penelitian ini bertujuan untuk mendapatkan isolat DNA bakteri beserta konsentrasi dan kemurniannya, menyeleksi media pertumbuhan bakteri, mendeteksi gen hdc, tdc dan ldc menggunakan multiplex PCR serta identifikasi bakteri.. Sampel yang digunakan yaitu ikan tuna beku, tongkol beku, cakalang beku, tuna loin, pindang tongkol potong dan pindang tongkol bumbu kuning serta kontrol positif menggunakan ikan tuna yang disimpan pada suhu ruang selama 3 hari. Penelitian terdiri dari tahap pra-pengayaan bakteri pada media marine broth dan lactose broth, isolasi DNA sampel tanpa dan hasil pra-pengayaan, uji kemurnian dan konsentrasi isolat serta amplifikasi gen target hdc, tdc, ldc menggunakan multiplex PCR. Hasil yang diperoleh yaitu kualitas isolat DNA bakteri pada umumnya sudah murni, dengan konsentrasi isolat 15,75-157,84 ng/µL. Teknik multiplex PCR berhasil mendeteksi gen hdc, tdc dan ldc pada ikan scombridae. Kondisi optimum amplifikasi PCR yaitu annealing pada suhu 50°C selama 90 detik. Gen yang terdeteksi pada sampel tanpa pra-pengayaan yaitu tdc, sedangkan ldc dan hdc ditemukan pada sampel hasil pra-pengayaan media lactose broth dan marine broth. Bakteri pembentuk amina biogenik teridentifikasi sebagai Enterococcus fecalis, M. morganii, E. aerogenes, Citrobacter sp., Hafnia paralvei dan Obesumbacterium proteus.

Global Transcriptomic Responses of Roseithermus sacchariphilus Strain RA in Media Supplemented with Beechwood Xylan

The majority of the members in order Rhodothermales are underexplored prokaryotic extremophiles. Roseithermus, a new genus within Rhodothermales, was first described in 2019. Roseithermus sacchariphilus is the only species in this genus. The current report aims to evaluate the transcriptomic responses of R. sacchariphilus strain RA when cultivated on beechwood xylan. Strain RA doubled its growth in Marine Broth (MB) containing xylan compared to Marine Broth (MB) alone. Strain RA harbors 54 potential glycosyl hydrolases (GHs) that are affiliated with 30 families, including cellulases (families GH 3, 5, 9, and 44) and hemicellulases (GH 2, 10, 16, 29, 31,43, 51, 53, 67, 78, 92, 106, 113, 130, and 154). The majority of these GHs were upregulated when the cells were grown in MB containing xylan medium and enzymatic activities for xylanase, endoglucanase, β-xylosidase, and β-glucosidase were elevated. Interestingly, with the introduction of xylan, five out of six cellulolytic genes were upregulated. Furthermore, approximately 1122 genes equivalent to one-third of the total genes for strain RA were upregulated. These upregulated genes were mostly involved in transportation, chemotaxis, and membrane components synthesis.

ISOLASI BAKTERI YANG BERSIMBION DENGAN ASCIDIAN Herdmania momus YANG MEMILIKI AKTIVITAS ANTIBAKTERI

Ascidian is marine invertebrates in coral reef ecosystems that produce many bioactive compounds for pharmacology. The presence of symbiotic bacteria with marine organisms is protected the host biota by producing secondary metabolites. The purpose of this study is to obtain symbiotic bacterial isolates with Herdmania momus ascidian, then to observe the antibacterial activity of these bacterial isolates against Escherichia coli, and Staphylococcus aureus. Isolation and culture of the symbiotic bacteria were made on Nutrient Agar and Zobell Marine Broth media. The antibacterial screening showed that the Herdmania momus symbiotic bacteria were able to inhibit the growth of Staphylococcus aureus and Escherichia coli.Keywords: ascidians, Herdmania momus, bacteria, isolation, antibacterialAbstak Ascidian adalah avetebrata laut di ekosistem terumbu karang yang banyak menghasilkan senyawa bioaktif untuk bidang farmakologi. Keberadaan bakteri yang bersimbion dengan organisme laut pada umumnya untuk melindungi biota yang ditumpanginya dan dirinya dengan cara menghasilkan senyawa metabolit sekunder. Tujuan dari penelitian ini yaitu untuk mendapatkan isolat bakteri yang bersimbion dengan ascidian Herdmania momus, kemudian mengamati aktivitas antibakteri dari isolat bakteri tersebut terhadap Escherichia coli, dan Staphylococcus aureus. Isolasi dan kultur bakteri yang bersimbion dengan ascidian dibuat pada media Nutrient Agar dan Zobell Marine Broth. Skrining aktivitas antibakteri menunjukkan isolat bakteri yang bersimbion dengan ascidian Herdmania momus mampu menghambat pertumbuhan organisme uji Staphylococcus aureus dan Escherichia coli.Kata kunci: ascidian, Herdmania momus, bakteri, isolasi, antibakteri

Cultivation technology development of Rhodothermus marinus DSM 16675

This work presents an evaluation of batch, fed-batch, and sequential batch cultivation techniques for production of R. marinus DSM 16675 and its exopolysaccharides (EPSs) and carotenoids in a bioreactor, using lysogeny broth (LB) and marine broth (MB), respectively, in both cases supplemented with 10 g/L maltose. Batch cultivation using LB supplemented with maltose (LBmalt) resulted in higher cell density (OD620 = 6.6) than use of MBmalt (OD620 = 1.7). Sequential batch cultivation increased the cell density threefold (OD620 = 20) in LBmalt and eightfold (OD620 = 14) in MBmalt. In both single and sequential batches, the production of carotenoids and EPSs using LBmalt was detected in the exponential phase and stationary phase, respectively, while in MBmalt formation of both products was detectable in both the exponential and stationary phases of the culture. Heteropolymeric EPSs were produced with an overall volumetric productivity (QE) of 0.67 (mg/L h) in MBmalt and the polymer contained xylose. In LB, QE was lower (0.1 mg/L h) and xylose could not be detected in the composition of the produced EPSs. In conclusion, this study showed the importance of a process design and medium source for production of R. marinus DSM 16675 and its metabolites.

Consideration of Influential Factors on Bioleaching of Gold Ore Using Iodide-Oxidizing Bacteria

Iodide-oxidizing bacteria (IOB) oxidize iodide into iodine and triiodide which can be utilized for gold dissolution. IOB can be therefore useful for gold leaching. This study examined the impact of incubation conditions such as concentration of the nutrient and iodide, initial bacterial cell number, incubation temperature, and shaking condition on the performance of the gold dissolution through the experiments incubating IOB in the culture medium containing the marine broth, potassium iodide and gold ore. The minimum necessary concentration of marine broth and potassium iodide for the complete gold dissolution were determined to be 18.7 g/L and 10.9 g/L respectively. The initial bacterial cell number had no effect on gold dissolution when it was 1 × 104 cells/mL or higher. Gold leaching with IOB should be operated under a temperature range of 30–35 °C, which was the optimal temperature range for IOB. The bacterial growth rate under shaking conditions was three times faster than that under static conditions. Shaking incubation effectively shortened the contact time compared to the static incubation. According to the pH and redox potential of the culture solution, the stable gold complex in the culture solution of this study could be designated as gold (I) diiodide.

ISOLASI DAN SKRINING MIKROBA PENGHASIL BIOSURFAKTAN DARI AIR LAUT YANG TERCEMAR MINYAK

ABSTRAK Mikroorganisme penghasil biosurfaktan telah diisolasi dari air laut yang tercemar minyak yang diambil dari beberapa lokasi dermaga di Indonesia. Lima dari 155 isolat yang diisolasi mampu menghasilkan biosurfaktan yang tinggi melalui proses fermentasi menggunakan medium produksi Marine Broth (Difco). Isolat ML4-10 yang diisolasi dari kawasan dermaga kilang minyak Pertamina di Cilacap menunjukkan kemampuan menghasilkan biosurfaktan tertinggi. Pada uji biosurfaktan yang dihasilkan oleh isolat ML4-10 menunjukkan bahwa aktifitas emulsifikasi dan oil displacement, berturut-turut adalah 54,1 ± 0,8 dan 10,5 ± 0,3. Biosurfaktan dari ML4-10 juga menunjukkan nilai positif pada uji oil drop test. Pada uji aktifitas emulsifikasi dan oil displacement menggunakan berbagai sumber minyak, biosurfaktan dari ML4-10 juga menunjukkan aktifitas yang tinggi, hal ini menunjukkan biosurfaktan mempunyai potensi aplikasi yang luas.Kata kunci: biosurfaktan, pencemaran minyak, air laut, mikroorganisme, isolat