The Potential Application of Cupriavidus necator as Polyhydroxyalkanoates Producer and Single Cell Protein: A Review on Scientific, Cultural and Religious Perspectives

Polyhydroxyalkanoates are environmentally friendly bioplastic compounds produced via the microbial route that offer an alternative to synthetic plastics due to their comparable durability and thermal stability. However, the high production cost as a result of carbon feedstock for microorganisms and the downstream recovery process narrow the usage of polyhydroxyalkanoates in various fields. Conversion of by products from the food and agricultural industries such as waste cooking oil, glycerol, palm sludge oil, oil palm trunk sap and soya waste into polyhydroxyalkanoates is an attractive approach that can minimize and/or add value to waste. Results and conclusion: Recently, there has been a lot of interest in exploring not just polyhydroxyalkanoates as valued-added products, but also PHA-producing bacteria as a nutritional food or feed source. It has been previously reported that the PHA-producing bacterium, Cupriavidus necator, can be utilized as a single cell protein (SCP) in animal feed owing to its high protein content. The mealworm beetle (Tenebrio molitor) has also been used as the model insect to evaluate the efficacy of Cupriavidus necator cells as a source of protein and to recover polyhydroxyalkanoate granules at the same time. The European Union has imposed strict regulations on the type of feedstock that can be used to ensure that the food chain is safe. In addition, there are religious and cultural concerns. This review will focus on the nutritional value of Cupriavidus necator as single cell protein and its safety as animal feed. The impact of using by-products from the agriculture and food industries as carbon feedstocks to produce single cell protein will be discussed, alongside societal acceptance of this practice. Conflict of interest: The authors declare no conflict of interest.