The bio‐control potential of Alcaligenes aquatilis against its associated cyanobacteria Lyngbya aestuarii

Abstract

AbstractCyanobacteria and heterotrophic bacteria show many similarities in their structure but are different based on their nutritional habits. Autotrophic cyanobacteria and heterotrophic bacteria coexist closely in their natural environments and are capable of a variety of interactions (synergistic, neutral, and antagonistic) due to the secretion of growth‐promoting/retarding (toxin) substances by the bacterial partner. In this study, the cyanobacteria Lyngbya aestuarii and its associated bacteria Alcaligenes aquatilis isolated from the mangrove water of Bhitarkanika showed an antagonistic interaction. The growth of axenic and co‐cultured (1:1; cyanobacteria to bacteria) cyanobacteria was examined under photoautotrophic conditions, to evaluate the interactions between the two groups. The bacteria were found to have cellulase and protease activity and were able to obstruct the growth of cyanobacteria under co‐culture conditions. Besides that, the bacteria secrete many allelochemicals like phenol, tannin, amino acids (alanine and aspartic acid), and hydroxamate siderophore to its surroundings which inhibit the growth and metabolism of the cyanobacteria under co‐cultured conditions. Findings from this study indicate its possible application for wastewater management.