Bakteri asam laktat penghasil antimikrobia pada tanaman sayur

TRIMULYONO, Guntur, Drs. Langkah Sembiring, M.Sc., Ph.D

2010 | Tesis | S2 Biologi

Penelitian mengenai bakteri asam laktat yang menghasilkan aktivitas antimikrobia telah dilakukan. Bakteri asam laktat diisolasi dari sampel sayuran berupa kentang, kubis, ubi jalar, dan wortel menggunakan medium MRS dengan metode enrichment dilanjutkan dengan pour plate dan dimurnikan dengan metode streak plate. Isolat bakteri asam laktat yang diperoleh diskrining kemampuannya dalam menghambat bakteri uji Pediococcus acidilactici LB 42. Isolat yang mampu menghambat P. acidilactici LB 42 diuji aktivitas antimikrobianya terhadap Staphylococcus aureus ATCC 25923, dan Escherichia coli ATCC 35218. Karakterisasi fenotipik isolat yang mampu menghambat bakteri uji dilakukan berdasarkan morfologi sel, karakter biokimiawi dan karakter fisiologis menggunakan metode profile matching dan numerical systematics. Isolasi bakteri asam laktat berhasil memperoleh sebanyak 40 isolat yang diduga sebagai bakteri asam laktat yang selanjutnya di skrining kemampuan penghambatannya terhadap P. acidilactici LB 42 yang 6 isolat di antaranya mampu menghambat pertumbuhan P. acidilactici LB 42. Isolat tersebut kemudian di uji kemampuan penghambatannya terhadap S. aureus ATCC 25923 dan E. coli ATCC 35218 memperoleh 4 isolat yang menunjukkan aktivitas antimikrobia, yaitu isolat Ke1, Ke3, Ku9, dan W2. Identifikasi terhadap ke-empat isolat tersebut menunjukkan bahwa isolat Ke1, Ke3, dan Ku9 merupakan anggota spesies Lactobacillus plantarum, sedangkan W2 merupakan anggota spesies Lactobacillus acidophilus. Dengan demikian bakteri asam laktat yang mempunyai kemampuan antimikrobia dapat diisolasi dari sampel sayuran.

The research on the lactic acid bacteria producing antimicrobial activity was conducted. The lactic acid bacteria were isolated from vegetable samples including potatoes, cabbages, sweet potatoes, and carrots using MRS medium with an enrichment method, followed by pour plate and purified by using a streak plate method. Lactic acid bacteria isolates obtained were screened for the ability to inhibit the tested bacteria of Pediococcus acidilactici LB 42. The isolates that inhibit P. acidilactici LB 42 were tested for their antimicrobial activity against Staphylococcus aureus ATCC 25923 and Escherichia coli ATCC 35218. Phenotypic characterization of isolates was done based on cell morphology, biochemical characters, and physiological characters by using a profile matching and numerical systematic method. Isolation of lactic acid bacteria obtained 40 isolates which indicated lactic acid bacteria were screened for antimicrobial activity against P. acidilactici LB 42. Six isolates among 40 were shown to inhibit the growth of P. acidilactici LB 42 in an agar well diffusion assay. These isolates were tested on the inhibition ability against Staphylococcus aureus ATCC 25923 and Escherichia coli ATCC 35218. The result showed that four isolates among six exhibited antimicrobial activity namely isolates of Ke1, Ke3, Ku9, and W2. Identification and characterization of the four isolates showed that the isolates of Ke1, Ke3, and Ku9 belonged to Lactobacillus plantarum, while those of W2 belonged to Lactobacillus acidophilus. Therefore that lactic acid bacteria with antimicrobial activity can be obtained from vegetable samples.

Kata Kunci : Bakteri asam laktat,Sayuran,Antimikroba, lactic acid bacteria, vegetables, antimicrobial