Isolation and optimization of polyhydroxybutyrate from Chlorella vulgaris using NaClO and ultrasonication aided chemical pretreatment methods

Abstract

The increasing use of food packaging makes plastic waste the biggest environmental issue. Since the use of conventional plastic comes from fossil polymers, so it is difficult to be decomposed by bacteria. The right solution is to replace it with bioplastics. This study uses Chlorella vulgaris as a producer of Poly-ß-hydroxybutyrate (PHB). PHB has characteristics such as biodegradability, thermoplasticity, hydrophobicity, biocompatibility with cells and tissues, and physical properties similar to polypropylene, which can potentially apply in food, pharmaceutical, and medical packaging. PHB is obtained by isolating biomass from Chlorella vulgaris. This research studied PHB isolation using chemical and mechanical cell disruption methods, namely NaClO and sonication, with variations in solvent concentration. The simplest and most economical method of isolation of C. vulgaris is the general stages of cell disruption, PHB precipitation, and PHB purification. The quantifying PHB method is by calculating the yield of PHB, then identifying PHB by FTIR, and testing the quality of the best PHB compounds by GCMS. The parameters used in this study are yield, PHB physical results, and PHB test results. In the condition of 0.6% w/v sample concentration and 1.37% w/v solvent concentration using ultrasonication, the best PHB isolation yield was 37.2%. GCMS sample results showed the presence of n-hexadecanoic acid (palmitic acid), 9-Octadecanoic acid (oleic acid), 2-Palmitoylglycerol, and Octadecanoic acid (stearic acid) as the main compounds that could potentially be bioplastic materials.