Arabian Journal for Science and Engineering https://doi.org/10.1007/s13369-018-3118-1 RESEARCH ARTICLE - BIOLOGICAL SCIENCES The Use of Palm Oil-Based Waste Cooking Oil to Enhance the Production of Polyhydroxybutyrate [P(3HB)] by Cupriavidus necator H16 Strain Hanisah Kamilah 1 · Adel Al-Gheethi 2 · Tajul Aris Yang 1 · Kumar Sudesh 3 Received: 19 May 2017 / Accepted: 4 February 2018 © King Fahd University of Petroleum & Minerals 2018 Abstract Waste cooking oil (WCO) is of increasing interest as an inexpensive feedstock to produce biodegradable plastic, poly(3- hydroxybutyrate) [P(3HB)]. In the present study, palm oil-based WCO (PO-WCO) was obtained from nine different locations. Palm oil-based fresh cooking oil (PO-FCO) and PO-WCO were characterised via proximate and physicochemical analysis, prior to being used as carbon sources for the biosynthesis of P(3HB) using Cupriavidus necator H16. It was shown that the free fatty acid, peroxide value, and saturated compounds in all batches of PO-WCO were higher compared to those in the PO-FCO. The cells produced 60–80 wt% P(3HB) with dry cell weight of 14–17 g/L. The weight average molecular weight ( M w ) was found to be 1.8 × 10 6 Da with a polydispersity ( M w / M n ) of 2.7 when PO-WCO was used as the carbon source. The PO-WCO was found to be suitable to be used as a sustainable carbon source for cell growth and P(3HB) biosynthesis. Keywords Biomaterial · Waste · Cooking oil · P(3HB) · C. necator H16 1 Introduction The rapid escalation in the human population along with their daily needs has led to the production of huge amounts of waste which is disposed into the environment. The petroleum-based plastic polymers are among one of the several types of products used extensively in daily life. B Hanisah Kamilah hanisahkamilah@gmail.com Adel Al-Gheethi alisaeed@uthm.edu.my Tajul Aris Yang Taris@usm.my Kumar Sudesh ksudesh@usm.my 1 Food Technology Division, School of Industrial Technology, Universiti Sains Malaysia, 11800 Gelugor, Penang, Malaysia 2 Department of Water and Environmental Engineering, Faculty of Civil and Environmental Engineering, Universiti Tun Hussein Onn Malaysia (UTHM), 86400 Parit Raja, Batu Pahat, Johor, Malaysia 3 Ecobiomaterial Research Laboratory, School of Biological Sciences, Universiti Sains Malaysia, 11800 Gelugor, Penang, Malaysia However, the main problem with these polymers is the resis- tance to degrade under natural environment. In this respect, the biopolymers such as poly(3-hydroxybutyrate) [P(3HB)] have high degradability but similar characteristics to petro- chemical plastics in terms of durability and stability [1–3]. In addition, P(3HB) is a class of thermoplastic biopoly- mers which is non-toxic, mouldable, and could be used for several applications including stiff packaging or in the production of high elastic materials [1,4]. P(3HB) is synthe- sised intracellularly in bacteria due to the deficiency of the essential nutrients, such as nitrogen, phosphorus, and mag- nesium [4,5]. Synthesis of P(3HB) is possible to be induced in the presence of high concentrations of a carbon source such as sugars, plant oils [6,7], animal fats [8], fatty acids, and glycerol [9,10]. Under conditions of limited nitrogen (N) and excess of carbon (C), a surfeit of acetyl-CoA and decrease in free coenzyme A concentration lead to the pro- duction of β-ketothiolase and, eventually, the formation of P(3HB). The enzyme β-ketothiolase is the main enzyme responsible for initiating the P(3HB) pathway that first forms acetoacetyl-CoA from acetyl-CoA, before reacting further with acetoacetyl-CoA reductase (PhaB) and polyhydrox- yalkanoate (PHA) synthase (PhaC) to form the end product P(3HB) (Fig. 1)[11,12]. 123