ประสิทธิภาพการกำจัดแอมโทเนียโดยเฮเทอโรโทรฟิคแบคทีเรียที่คัดแยกจากฟาร์มเพาะเลี้ยงกุ้งขาว(Litopenaeus vannamei)

Abstract

Ammonium removal for aquaculture ponds is significant to prevent aquatic animals from ammonium toxicity. This study, ammonium oxidizing bacteria strains SRNB23, SRNB35, SRNB78, SRNB79 and SKNB4 were isolated from sediment and water samples that collected from white shrimp farms. Each sample was enriched in modified Pep-Beef-AOM medium for 28 days. Ammonium removal ability was preliminary screened by Griess-llosvay method. Morphological characteristics showed that strains SRNB23, SRNB35, SRNB78 and SKNB4 were Gram negative and rod shape, while strain SRNB79 was gram positive, rod shape and had endospore formation. Based on 165 RNA gene sequencing data and phylogenetic analysis, strains SRNB23, SRNB35 and SRNB78 were identified as Alcaligenes sp. with similarity ranges of 98%, 91% and 99%, respectively. While strains SRNB79 and SKNB4 were identified as Oceanobacillus profundus and Halomonas aquamarina with similarity ranges of 99% and 99.7%, respectively. The result of ammonium removal efficiency showed that strains SRNB23 and SRNB35 have the highest ammonium removal ability for 91.75% and 91.21%, respectively. While only three isolates including SRNB78, SRNB79 and SKNB4 exhibited nitrate production and showed ammonium removal efficiency with initial concentration of 799-871 mg-N/L for 55.57%, 51.37% and 20.32%, respectively. Mixture of SRNB23 and SRNB35 had a highest ammonium removal efficiency of 66.07% and the best ratio of 30:70 had an ammonium removal efficiency of 59.72%. The, the single and mixture of bacteria were examined for treating of saline ammonium waste water with initial ammomium concentration of 461-467 mg-N/L from shrimp farm. The result showed that a mixture (SRNB23:SRNB35) had the highest ammonium removal efficiency of 63.07%