Abstract: Since polyhydroxyalkanoates (PHAs) can be obtained by utilizing organic waste as a substrate, they form one of the most suitable classes of organic acids with many applications, ranging from medical supplies to energy and biorefinery products. In total, PHAs are found in at least in 150 different molecular forms, with the basic differences determined by the length of the carbon skeleton (4 to 14 C-bonds) and the radicals, which are formed by many organic groups. These characteristics make up their unique physicochemical properties, biodegradability and nontoxicity. Many new approaches are now being developed to obtain PHAs and modify these molecules into new green chemicals as well as renewable alternatives for petroleum and other non-sustainable compounds. This mini review gives insight into the genetic characteristics of PHA synthases, the most important enzyme group related to this compound. This review addresses chemical techniques to modify PHAs to obtain compounds with a high market value. Therefore, this work shows new applications and possibilities for PHA, such as drug-delivery systems, building block chemicals, new polymeric structures for tissue scaffolds and certain energetic compounds, such as n-butanol..