Antimicrobial effect of a cyclic peptide Nostophycin isolated from wastewater cyanobacteria, Nostoc calcicola

Cyanobacterial features conspicuous researchers due to their capability of synthesis of various bioactive compounds, diverse range of habitats, wide diversity and morphological variability. Cyanobacteria are gram negative, photosynthetic and ubiquitous bacteria, which known as a primary producer (Gademann & Portmann, 2008). Availability in the extreme environment and unique feature of cyanobacteria, considered it to be future pioneer for research (Kulasooriya, 2011; Potts, 1999; Scherer et al., 1988; Scherer & Potts, 1989). According to Kalaitzis et al. (2009) cyanobacteria can produce immense range of bioactive compounds which help in survival in endurance and competitive ecological niche. Bioactive metabolites synthesized by Nostoc sp has been applied as a biofertilizer (Ghazal et al., 2018; Win et al., 2018), anticancer (Moore, 1996), antifungal (El-Sheekh et al., 2014), antibacterial (Ploutno & Carmeli, 2000), antiviral (Botos & Wlodawer, 2003) and enzyme-inhibiting (MazurMarzec et al., 2018). These bioactive compounds are explored and identified as peptides, alkaloids, terpenoids, fatty acid and lipopolysaccharides (Chorus, 2012; Dembitsky & Řezanka, 2005; Dittmann et al., 2001; Nowruzi et al., 2012; Parmar et al., 2011). Allelochemicals influence their own growth potential, other microbes in their vicinity, associated microorganisms, higher plants and animals. Cyanobacteria synthesize nitrogen storage material, new proteins, change pigmentation, excrete and store some other compounds, in response to environmental stress, temperature, pH, nutrient availability and light intensity (Mendes & Vermelho, 2013; Priya et al., 2015; Singh, 2014).