Preservation of lactic acid bacteria in glycerol and by lyophilization

anglais. The preservation of Lactic Acid Bacteria (LAB) needs the most suitable method in order to prolong the life time of LAB and keep their potencies. Four LAB isolates i.e. DSS 2.1, 03, RKN5/l and L casei 581 had been preserved. In this experiment, two methods of LAB preservation were compared. The first was the conventional method of freezing the cells in 40 percent glycerol and the freeze drying method (lyophilization). The cell viability and lactic acid production were evaluated after preservation for 0, 3, 6, 9 and 12 moths. The concentration of total viable LAB cells of DSS2.1; 03; RKN5/l and L. casei 581 before preservation were 5.8 x 10 at the power of 12; 5.2 x 10 at the power of 12; 2.4 x 10 at the power of 12 and 9 x 10 at the power of 10 cfu/g respectively. After being preserved, the viable cells decreased. The freeze drying method showed more effective results compared to the glycerol preservation. Lactic acid production of the four isolates before preserved were DSS2.1 (9.19 mg/ml); 03 (7.3 mg/ml), RKN5/1 (8.46 mg/ml), and L. casei 581 (11.09 mg/ml) respectively. Lactic acid production of the isolates preserved in 40 percent glycerol for 12 months decreased as shown by DSS2.1 (74.2 percent); 03 (83.3 percent), RKN5/l (62.3 percent), and L. casei 581 (70.8 percent) respectively. Whereas lactic acid production of the isolates preserved by lyophilization for 12 months subsequently were DSS2.1 (41.2 percent); 03 (40.5 percent), RKN5/1 (33.6 percent), and L. casei 581 (39.2 percent), respectively. Lyophilized cells LAB. produced higher lactic acid compared to the cells preserved in 40 percent glycerol

indonésien. Penyimpanan kultur bakteri potensi dalam jangka waktu panjang memerlukan teknik yang tepat agar terjamin kelangsungan hidupnya dan potensinya tidak hilang. Pada percobaan ini dilakukan dan cara penyimpanan Bakteri Asam Laktat (BAL) yaitu dengan dilapisi larutan gliserol 40 percent dan dengan teknik liofilisasi. Pengujian terhadap 3 isolat BAL yaitu DSS 2.1, 03, RKN 5/1 dan 1 galur Lactobacillus casei 581 dilakukan setelah penyimpanan 0, 3, 6, 9, dan 12 bulan terhadap viabilitas sel dan produksi laktat. Jumlah sel awal (cfu/mg) sebelum penyimpanan isolat DSS 2.1 (5,8x10 pangkat 12), RKN 5/1 (2,4x10 pangkat 12), dan L. casei 581 (9x10 pangkat 10). Setelah penyimpanan terdapat penurunan jumlah sel pada penyimpanan dalam gliserol maupun secara liofilisasi. Hasil pengamatan menunjukkan bahwa viabilitas sel lebih baik dengan teknik penyimpanan secara liofilisasi dari pada dengan larutan gliserol 40 persen. Produksi asam laktat pada isolat sebelum penyimpanan pada DSS 2.1 (9,19 mg/ml), 03 (7,30 mg/ml), RKN 5/1 (8,46 mg/ml), dan L. Casei 581 (11,09 mg/ml). Produksi asam laktat oleh isolat dengan penyimpanan dalam gliserol selama 12 bulan mengalami penurunan masing-masing DSS2.1 (41,2 persen); 03 (40,5 persen); RKN5/1 (33,6 persen) dan L. casei 581 (39,2 persen). Produksi asam laktat yang dihasilkan lebih tinggi pada penyimpanan secara liofilisasi dibandingkan dengan penyimpanan dalam larutan gliserol 40 persen