APLIKASI BAKTERIOFAGA ?BT & ?BC SEBAGAI AGEN BIOKONTROL PEMBENTUKAN BIOFILM VIBRIO SP.U7

• Main Author: Marweslie, Mario
• Format: Final Project
• Language: Indonesia
• Subjects: Teknik (Rekayasa, enjinering dan kegiatan berkaitan)
• Online Access: https://digilib.itb.ac.id/gdl/view/55094
• Institution: Institut Teknologi Bandung

The increase in human population has led to an increase in food production, especially in the aquaculture sector, one of which is white shrimp. However, intensive shrimp farming still has challenges, namely vibriosis which can cause shrimp mortality up to 100%. Vibriosis occurs when the Vibrio count reaches more than 104 CFU/ml or when a biofilm is formed. The current treatment is dealing with the use of biological agents. One possible biological agent is bacteriophage. Bacteriophages have the ability to lyse bacteria and are able to prevent and eradicate biofilms, so they can be used as biocontrol agents. However, in its application, bacteriophages need to be characterized and optimized so that they can be effective as Vibrio biocontrol agents in white shrimp. In previous studies, Vibrio and bacteriophage were isolated from shrimp and pond water samples. From these results, one of the isolates was Vibrio sp.U7, and from these isolates, ?Bt & ?Bc bacteriophages were obtained. The aims of this study were (1) to determine the optimal Multiplicity Of Infection (MOI), (2) to determine the ability to inhibit bacteria, (3) to determine the latency time and burst size, (4) to determine the ability to prevent biofilms, and (5) to determine the ability to eradicate biofilms. Determination of the optimal MOI was carried out at the ratio of the number of bacteriophages and bacteria 0.01; 0.1; 1; 10; 100 by spot assay. Determining the inhibitory ability of bacteriophages was carried out by adding ?Bt, ?Bc, and cocktail bacteriophages to Vibrio sp.U7 (108 CFU/ml) for 5 hours measured every 30 minutes by spectrophotometry. Latent time and burst size were determined by growing bacteriophages for 135 minutes and counting the number of bacteriophages every 30 minutes by spot assay method. The biofilm prevention and eradication test was carried out on a 96-well plate. The addition of the bacteriophage was added together with the bacteria in the preventive test, while in the eradication test it was added after the bacteria were incubated for 48 hours or the biofilm was formed. The results showed that the optimum MOI of ?Bt & ?Bc bacteriophages was 10 with the titers of ?Bt and ?Bc bacteriophages respectively 2x1017 and 4x1019 PFU/ml. The latency time of ?Bt and ?Bc bacteriophages was 75 and 45 minutes, respectively, with burst sizes of 2.52 x 104 and 5 x 105 PFU/cell. In the inhibition test, ?Bt bacteriophage treatment inhibited the growth of vibrios 30 minutes after the addition of bacteriophages and decreased the number of vibrios after 2 hours (? = 9.81 x 10-3 minutes-1). The ?Bc bacteriophage treatment also decreased the number of vibrios 2 hours after addition (? = 1.01 x 10-2 minutes-1) while the cocktail bacteriophage treatment did not decrease the number but reduced the vibrio growth rate (? = 1.22 x 10-2 minutes-1) with a control growth rate of 1.31 x 10-2 min-1 (P > 0.05). In the biofilm prevention test for 24 hours, ?Bt, ?Bc, and cocktail bacteriophages respectively showed a percentage of biofilm inhibition of 67.65%; 53.86%, and 25.16% (P < 0.05). In the biofilm eradication test, after 6 hours of adding bacteriophages, the absorbance decreased in the ?Bt bacteriophage treatment and the cocktail was 29.18% and 5.84%, respectively, while the ?Bc bacteriophage treatment did not show any eradication from the biofilm. Overall, ?Bt bacteriophages have the ability to inhibit Vibrio growth and are able to prevent and eradicate biofilms better than ?Bc and cocktail bacteriophages. So that ?Bt bacteriophages may be applied as biofilm biocontrol agents on Vibrios.