Optimasi Sumber Karbon Dan Nitrogen Sebagai Co-Substrat Untuk Pertumbuhan Bakteri Probiotik Pseudomonas sp. - Doresti, Livvy; Setyati, Willis Ari; Widowati, Ita (Departemen Ilmu Kelautan, Fakultas PerikanJurusan Ilmu Kelautan, Universitas Diponegoro)
ABSTRAK : Pencemaran limbah organik pada sistem tambak udang merupakan salah satu faktor yang menyebabkan terjadinya penurunan produksi. Limbah organik seperti sisa pakan dan feses terakumulasi pada substrat perairan sehingga kualitas air menurun dan timbul penyakit. Pseudomonas sp. merupakan bakteri probiotik yang dapat menghasilkan enzim pendegradasi protein dan amilum, limbah organik yang banyak ditemukan di sistem tambak. Penelitian ini dilakukan penentuan jenis dan optimasi sumber karbon dan nitrogen untuk pertumbuhan Pseudomonas sp. dalam upaya mengetahui komposisi medium yang lebih baik untuk produksi biomassa bakteri probiotik. Eksperimen yang dilakukan berupa penentuan sumber karbon yang meliputi glukosa, fruktosa dan molase. Penentuan sumber nitrogen meliputi ammonium nitrat, ammonium klorida dan urea. Pengamatan pertumbuhan dilakukan dengan metode spektrofotometri berdasarkan perubahan optical density pada kultur bakteri. Pertumbuhan Pseudomonas sp. memilik fase lag (adaptasi) pada jam ke-0 hingga jam ke-6. Hasil penelitian penentuan jenis sumber karbon diperoleh glukosa dengan nilai OD laju pertumbuhan tertinggi yaitu 0.118±0.001 dan penentuan jenis sumber nitrogen diperoleh ammonium nitrat dengan nilai OD laju pertumbuhan 0.117±0.000. Sumber karbon glukosa optimum pada konsentrasi 4% dengan nilai OD laju pertumbuhan 0.106±0.000 dan sumber nitrogen ammonium nitrat optimum pada konsentrasi 0.5% dengan nilai OD laju pertumbuhan 0.112±0.002. ABSTRACT : The contamination of organic waste in the shrimp pond system is one of the factors that lowering shrimp production. Organic waste such as leftover feed and fecal matter accumulated in the waters substrate decreasing the water quality and emerging disease. Pseudomonas sp. is a probiotic bacteria which can produce enzymes that degrade proteins and amylum-an organic waste commonly found in pond systems. This study was conducted to determine the type and optimization of carbon and nitrogen source for the growth of Pseudomonas sp. in an effort to know the composition of a better medium for probiotic biomass production. Experiments were carried out in the form of determination of carbon sources include glucose, fructose and molasses. Determination of nitrogen sources include ammonium nitrate, ammonium chloride and urea. The observations of growth rate was done by spectrophotometric method based on optical density in a bacterial culture. The growth of Pseudomonas sp. reached lag phase (adaptation) on 0 up to 6 hours. Then, on 6 up to 36 hours the bacterium has exponential phase which is characterized by the significant growth. The results of the determination of carbon source obtained glucose was the highest growth rate 0118 ± 0001 and determination of the nitrogen source obtained ammonium nitrate with growth rate 0117 ± 0000 by the OD value. Optimization carbon source was at 4% concentration of glucose with the growth rate 0.106 ± 0.000, and also the optimization nitrogen source was at 0.5% concentration of ammonium nitrate with growth rate of 0112 ± 0002 by the OD value.