Polyhydroxyalkanoate nanoparticles produced by marine bacteria cultivated on cost effective Mediterranean algal hydrolysate media.

• Halomonas isolates ASL10 and ASL10 can produce PHA by using cost effective algal hydrolysates media. • The utilization of C. mediterranea hydrolysates as C and N sources yielded the maximum PHA concentrations. • PHA-NPs showed a new antibacterial attribute against several reference strains. • PHA-NPs revealed relatively low hemolysis which affirms the safety of the proposed NPs for different applications. Algae are omnipresent in all seas and oceans, which make thema target for many applications such as bio-fertilizers, fish feeding and removal of heavy metals. In the present study, different algal species were examined as sustainable alternatives substrates for PHA production by Halomonas sp. Several media simulations were utilized to achieve high polymer productivity. The maximum poly(3-hydroxybutyrate) (PHB) concentrations were determined by using Corallina mediterranea hydrolysates as a carbon and nitrogen source. The isolates Halomonas pacifica ASL10 and Halomonas salifodiane ASL11 were found to be able to produce PHA by 67 % wt and 63 % wt CDW, respectively. PHB nanoparticles (NPs) had high zeta potential values and small particle sizes. These properties make it suitable for several drug delivery and pharmaceutical applications. Interestingly, NPs showed a potent antibacterial activity against several reference strains. The antibacterial efficacy of PHA-NPs has not been previously studied, thus this study opens a promising use of PHA-NPs. [ABSTRACT FROM AUTHOR]