Journal of the Marine Biological Association of India

Characterization of starch utilizing bacterial symbionts from marine fishes of different feeding habits

Volume 65 Issue 2

Asha Augustine and Imelda Joseph

10.6024/jmbai.2023.65.2.2449-03

Abstract

Research on the microflora of farmed fishes is extensive, but studies on wild fishes’ microflora are limited. We isolated cultivable bacteria from many wild-caught marine fish species with different feeding habits from different coastal states of India. Bacterial species identity was determined by 16S rRNA gene sequencing for all the isolates. From Brownback trevally Carangoides praeustus, Indian seven-finger threadfin Filimanus similis, Largescale mullet Liza macrolepis, Indian oil sardine Sardinella longiceps and Pugnose pony fish Secutor insidiator, we could screen and characterize five amylolytic bacterial isolates. The phenotypic and genotypic (16S rRNA gene) characterization of the strains have confirmed the species as Bacillus nealsonii strain TCPS1 (GenBank Accession no. JN710379), Vibrio alginolyticus strain CFSS2C2 (GenBank Accession no.JN710378), Bacillus atrophaeus strain MLMS3 (GenBank Accession no. JN712298), Pseudomonas stutzeri strain KSLS4C3 (GenBank Accession no. JN710377), and Aeromonas hydrophila strain KSIS5 (GenBank Accession no. JN712299). For a 5-day experiment, significant (P<0.05) variation in starch utilization was recorded by the five symbionts. The rates of utilization at an exponential stage of growth were studied and the maximum rate for starch utilization was shown by A. hydrophila strain KSIS5 (0.79 mg maltose ml-1 medium h-1). The results may be useful for further utilization of these species in the aquafeed industry or as a potential source of amylase in agriculture and allied sectors

Keywords

Symbiotic bacteria, marine fishes, 16S rRNA gene, starch utilization, amylase enzyme

Date : 15-11-2023