An Economical Source for Peroxidase: Maize Cobs*

Abstract

According to the current situation of peroxidase (POD), the relevant studies on this enzyme indicated its importance as a tool in clinical biochemistry and different industrial fields. Most of these studies used the fruits and vegetables as source of this enzyme. So that in order to couple the growing requirements for POD with the recent demands for reducing disposal volume by recycling the plant waste, the aim of the present study was to extract POD through management of municipal bio-waste of Iraqi maize species. A simple, green and economical method was used to extract this enzyme. Our results revealed that maize cobs are rich sources of POD, where the activity of this enzyme was found to be 7035.54 U/g of cobs. In pilot experiments this enzyme was extracted from the cobs using an efficient extraction buffer with either Cetyl Trimethyl Ammonium Bromide (CTAB), or sonication. To purify the extracted enzyme the previous step was followed by aqueous two phase extraction (ATPE) using 20% (w/v) polyethylene glycol (PEG) and 9% (w/v) ammonium sulfate. The obtained results indicated that POD was partially purified with 2.36 fold of purification and 81.78% recovery. The optimum temperature and pH of the extracted POD activity as well as the enzyme thermal stability were determined and found to be 20 °C, pH 6, and stable at 60 °C for 10 min respectively. Out of the present study findings, it can be concluded that maize cobs are rich source for POD and the applied protocol could be potentially used for POD extraction with high level. Meantime, this study suggested a new strategy by which the environmental pollution results from accumulation of plant waste can be reduced.