There has been considerable interest in the development and production of biodegradable polymer to solve the current problem of pollution caused by the continuous use of synthetic polymer of petroleum origin. Polyhydroxyalkanoates (PHAs) are known to be accumulated as intracellular inclusion in some bacteria. The materials properties exhibited by PHAs, ranging from stiff, brittle to rubber-like makes it a close substitute for the synthetic plastic. The high cost of PHAs production has restricted its applications. The possibility of producing this polymer commercially and at comparable cost has been the main focus in this area. Key words: Polyhydroxyalkanoates, biodegradable polymer, bioplastic, poly(3-hydroxybutyrate), biosynthesis.

The synthesis of zeolites from fly ash has become an increasingly promising remedy to the crisis of coal fly ash production and disposal in South Africa. In recent studies, South African fly ash was proven to be a suitable feedstock for the synthesis of essential industrially used zeolite A. However, the process involves a costly energy intensive step whereby fly ash is fused at high temperatures, which may make the process economically unattractive on a large scale. The aim of this study is to investigate the possibility of replacing high temperature fusion with less energy intensive sonochemical treatment for the synthesis of zeolite A. Sonochemical treatment was first thought possible due to the violent cavitation caused by high intensity sonication. The results of the study showed that fusion can be replaced by 10 min of high intensity sonication. The incorporation of sonication also consequently reduced the crystallization temperature of the process making it possible to synthesize a pure phase zeolite A at lower temperatures and reduced times. This study effectively developed a novel process to replace the energy intensive fusion step with a short, easy and inexpensive treatment. Scale up of this synthesis approach may proffer a promising alternative option to the anticipated energy demand of the synthesis of fly ash-based zeolite with fusion method.

In this paper, cellulose nanocrystals (CNCs) were isolated from the cellulose extracted from cocoa pod husk waste, followed by characterization using XRD, FT-IR, TGA, SEM and TEM to determine its crystallinity, structural properties, thermal characteristics, morphology and dimensions respectively. The result revealed that the cocoa pod husk amorphous segments containing hemicelluloses and lignin were extensively removed with increasing chemical treatments leading to increased purity, crystallinity index and thermal stability of the extracted materials. The diameter, length and crystallinity index of the CNC isolated from the CPH are 10–60 nm, 41–155 nm and 67.60% respectively.

This study reviewed five different nonconventional technologies which are aligned with green concepts of product recovery from raw materials on industrial scale, with minimal energy consumption and chemical use. Namely, this study reviewed supercritical fluid extraction (SCFE), pressurized liquid extraction (PLE), microwave-assisted extraction (MAE), ultrasound extraction (UAE) and pulsed electric fields extraction (PEFE). This paper provides an overview of relevant innovative work done in process industries on different plant matrices for functional value-added compounds and byproduct production. A comparison of the five extraction methods showed the supercritical CO₂ (SC-CO₂) process to be more reliable despite some limitations and challenges in terms of extraction yield and solubility of some bioactive compounds when applied in processing industries. However, these challenges can be solved by using ionic liquids as a trainer or cosolvent to supercritical CO₂ during the extraction process. The choice of ionic liquid over organic solvents used to enhance extraction yield and solubility is based on properties such as hydrophobicity, polarity and selectivity in addition to a safe environment.