PENGENDALIAN BIOFILM Aeromonas hydrophila PADA PERMUKAAN SISIK IKAN DAN PLASTIK PVC DENGAN SENYAWA ANTIMIKROBA
BAKTERI ASAM LAKTAT PERAIRAN TAWAR
ABSTRAK
Wabah penyakit bakteri berdampak terhadap penurunan mutu ikan segar dan penyebab kematian berbagai jenis ikan tawar pada sistem akuakultur. A. hydrophila ditemukan pada perairan tawar dalam bentuk biofilm sebagai penyebab motil aeromonas septicemia (MAS). Penelitian ini bertujuan untuk mengendalikan biofilm A. hydrophila dengan memanfaatkan senyawa antimikroba bakteri asam laktat (BAL) yang diisolasi dari usus ikan Nila Sumatera Utara. Isolasi BAL dari usus ikan Nila (Oreochromis niloticus) dilakukan menggunakan media selektif deMan Rogosa Sharpe Agar (MRSA). Seleksi untuk memperoleh kandidat probiotik dilakukan terhadap 21 isolat dengan uji antagonis terhadap A. hydrophila dengan metode difusi cakram. Isolat potensial dengan diameter zona hambat terbesar adalah isolat US6 yaitu 13,3 mm.
A. hydrophila membentuk biofilm dengan jumlah sel tertinggi pada permukaan sisik ikan sebesar 10 log CFU/lempeng dan pada plastik PVC (Polyvinyl Chloride) 8 log CFU/lempeng pada hari kelima. Pengendalian biofilm dilakukan dengan senyawa antimikroba ekstrak kasar isolat US6 selama 1 jam. Sel yang menempel dilepas dengan 0,5 g glass beads. Pengurangan jumlah sel pada lempeng sisik ikan sebesar 4 log CFU/lempeng dan pada plastik PVC 2 log CFU/lempeng. Ketahanan senyawa antimikroba diujikan terhadap berbagai pH, suhu dan surfaktan. Kondisi asam dan basa divariasikan pada pH 2, 4, 6, 8 dan 10. Senyawa antimikroba aktif pada kondisi pH 2 hingga pH 10 serta aktif hingga suhu 80 o
Kata kunci : Biofilm, A. hydrophila, sisik dan plastik PVC, bakteri asam laktat
C. Penambahan EDTA dan Tween 80 mempengaruhi aktivitas senyawa antimikroba dan diperoleh zona sebesar masing-masing sebesar 3 mm dan 5 mm. Senyawa antimikroba BAL isolat US6 menghambat pertumbuhan sel biofilm A. hydrophila pada sisik ikan dan lempeng plastik PVC.
CONTROLLING BIOFILM OF Aeromonas hydrophila ON FISH SCALES AND PLASTICS PVC SURFACES WITH ANTIMICROBIAL
COMPOUNDS LACTIC ACID BACTERIA FROM FRESHWATER
ABSTRACT
Outbreaks of bacterial diseases could affect on degradation of freshwater fish and cause of death of many species of freshwater fish in aquaculture systems. A. hydrophila found in freshwater in the form of biofilms and cause of Motile Aeromonas Septicemia (MAS). To overcome of this pathogens attack, a possible attack effective way to make use of lactic acid bacteria (LAB) as a probiotic agent. Controlling biofilm A. hydrophila has been done starting with LAB isolation in waters, the selection of potential isolates in inhibiting biofilm cells of
A. hydrophila and the control of on fish scales and plastic PVC using a crude extract of LAB antimicrobial compounds. LAB was isolated from intestinal Nile Tilapia (Oreochromis niloticus) using selective media deMan Rogosa Sharpe Agar (MRSA). Selection of potential LAB as candidate probiotics was conducted from antagonistic test against A. hydrophila. Isolate US6 was found as potensial biocontrol agent which should the highest inhibition zone of 13.3 mm. Biofilm with the highest number of cells on the surface of the fish scales by 10 log CFU/chip and the plastic PVC (Polyvinyl Chloride) 8 log CFU/chip on the fifth day. Controlling biofilms was perform had been done with antimicrobial compounds in crude extract US6 isolate for 1 hour contact time. Cells were removed with 0.5 g of glass beads. Reduction in the number of cells on the plate of fish scales by 4 log CFU/chip and the plastic PVC 2 log CFU/chip. Characterization of antimicrobial compounds was tested to by its resistance to pH, temperature and surfactants. Antimicrobial compound was active as pH range of 2 to 10 and actives in temperature 80 oC. The addition of EDTA and Tween 80 that showed by activity in inhibiting clear zone 3 mm and 5 mm. It could be concluded that the antimicrobial compound of lactic acid bacteria inhibits biofilm
A. hydrophila on fish scales and PVC plastic.
Keywords:Biofilm, A. hydrophila, fish scales and plastics PVC, lactic acid bacteria
