The use of poly(3-hydroxybutyrate), C-phycocyanin, and phenolic compounds extracted from Spirulina sp. LEB 18 in latex paint formulations

Commercial paints are produced using components that can be harmful to the environment. In light of this, our study aimed to reduce these drawbacks by investigating water-based paints in which the latex resin (polyvinyl acetate [PVA]) was replaced with poly(3-hydroxybutyrate) (PHB) extracted from Spirulina sp. LEB 18. In addition, C-phycocyanin and phenolic compounds, both also extracted from this microalga, were added to the paints for coloration and antimicrobial properties, respectively. Characterization analyses indicate that paint with 9.2% PHB and 6.1% limonene performs better in the following aspects: density (1.47 g cm(-3)), solids (41.5%) and pigment contents (38.4%), hiding power (94.2%), abrasion resistance (123 cycles), adhesion (5-15% area removed), drying time (90 min), reflectance (90%), and emissivity (0.80). Moreover, the biocolorant C-phycocyanin, besides conferring color, also provides better coverage by the paints. At a concentration of 0.8%, the phenolic compounds are the most effective among the biocides tested. Overall, we found that it is possible to develop a product similar to commercial ones using natural substances extracted from microalgae, which have not yet been used in formulations of paint. Thus, this study contributes to a sustainable alternative for paint formulation.