Open Conference Systems, 3rd KOBI Congress, International and National Conferences

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The Abundance and Potential Rate of Denitrifying and Nitrate-ammonifying Bacteria in Intensive Shrimp Farming Systems
Rizal Khoirun Alfisah

Last modified: 2020-11-20

Abstract


The presence of inorganic nitrogen compounds in the intensive shrimp farming will not be separated from the nitrogen cycle process. Nitrogen cycle always involves microbiological process including the activity of microorganisms such as denitrification and nitrate-ammonification. This study aimed to analyze the abundance and potential rate of denitrifying and nitrate-ammonifying bacteria over shrimp cultivation time. Water samples were collected on shrimp pond of Balai Layanan Usaha Produksi Perikanan Budidaya (BLUPPB) Karawang in West Java between January and March 2019. Water sampling was performed randomly at four points representing area of pond. Water samples were collected using sterile bottle at depth of 60 cm. Composite assessment was conducted on samples from each point. Bacterial abundances was analyzed using Most Probable Number (MPN) method. The potential rate of nitrate reduction activity was measured by analyzing nitrate, nitrite, and ammonium content with spectrophotometer. Potential rate of bacteria was calculated with Michaelis-Menten kinetics. The highest abundance of denitrifying bacteria was 3.415 log cells mL-1 on 89 days of cultivation, whereas nitrate-ammonifying bacteria was 3.079 log cells mL-1 on 60 days of cultivation. Based on the Michaelis-Menten kinetics, the affinity of enzymes related to nitrate reduction from denitrifying bacteria was higher than nitrate-ammonifying bacteria. Generally, denitrifying bacteria was the most dominant activity in nitrate reduction and more abundant than nitrate-ammonifying bacteria over shrimp cultivation.


Keywords


Inorganic nitrogen, MPN, nitrate reduction, shrimp farming