**1. Introduction**

Mycotoxins constitute a large number of naturally-occurring fungal secondary metabolites with considerable toxic impacts in plant and animal products, especially in developing countries [1]. These fungi usually attack cereals and other crops on the field or in storage, thereby causing significant economic losses and a ffecting trade globally. Furthermore, the presence of mycotoxins in feed and food commodities is a major health concern as the toxic e ffects cause serious problems to the health of animals, and ultimately humans. The major toxins of concern include aflatoxins (AFB1, AFB2, AFG1, AFG2), ochratoxinA OTA, fumonisins (FB1, FB2) and trichothecenes (ZEA, HT-2, T-2, and DON), which are placed in group 1, group 2 and group 3, respectively. According to the International Agency of Research on Cancer (IARC), AFB1 has been recognized as a class 1 carcinogen for animals and

humans [2]. Animals often show symptoms of mycotoxicosis even when these mycotoxins are present below permitted levels. This is probably a result of the negative effects of the synergistic interactions between various mycotoxins when they occur simultaneously in the same feed [3].

Although palm kernel cake (PKC) has been commonly used in ruminant feed, its use in poultry, swine, and fish diets is limited due to its high fiber content [4]. While PKC is a valuable source of protein and energy, it is susceptible to infection with mycotoxin-producing fungi. It is abundantly produced in mainly in the equatorial tropics, including South East Asia, Africa and South America. The incidence and severity of the growing number of reports concerning the presence of mycotoxins in feed and food highlights the heightened need for practical detoxification procedures [3,5,6]. Numerous strategies involving physical, chemical and biological methods have been explored in order to detoxify mycotoxin-contaminated food and feed materials [7]. The successful removal of mycotoxins from contaminated agricultural commodities using biological and chemical methods is hindered by several issues [8]. Some of these include safety issues, failure to effectively inactivate different mycotoxins simultaneously, limited efficacy, potential loss of nutritional quality and unfavorable cost implications. Adsorption is one of the most effective and attractive physical processes for mycotoxin removal. Its major advantage is that it has minimal to no detrimental effects on the animal and this often does not outweigh the benefits gained from the high removal efficiency. The efficacy of adsorption appears to depend on the chemical structure and interactions between the solvent, adsorbate and adsorbent [9]. Several studies have reported the applicability of some inorganic and organic adsorbents such as activated charcoal, clay, yeas<sup>t</sup> cell wall, hydrated sodium calcium aluminosilicates (HSCAS) and polymers for the binding and removal of mycotoxins [6,10–13]. In these cases, single adsorbents have been shown to be effective against one or two specific mycotoxins while few adsorbents may be used for various mycotoxins. However, none of them has been effective against all toxins [3,10,14,15]. Amongst numerous adsorbents, chitosan (CTS) is an effective, eco-friendly polymer and low-cost adsorbent which is used for the removal of pollutant effluents even at low concentrations because of its excellent adsorption capability [16].

Chitosan is a polyaminosaccharide that is derived through the deacetylation of chitin and it is predominantly comprised of unbranched chains of β-(1, 4)-linked 2-deoxy-2-amino-d-glucopyranose units. Chitin and CTS are the second most abundant bio- polymers after cellulose. They can be isolated from shells of crustaceans such as crabs, krills, shrimps and cell walls of some fungi [17]. Chitosan appears to be more attractive for use as adsorbent because of its beneficial properties such as hydrophilicity, biodegradability, non-toxic nature and anti-bacterial property. Likewise, CTS is a good scavenger for pollutants binding owing to the presence of amine (–NH2) and hydroxyl (–OH) functional groups in its structure; these function as coordination and reaction sites [18]. In addition, CTS sorbents are conventionally used for adsorption of anionic pollutants from aqueous solutions because of their polycationic nature.

Chitin has very poor solubility in most organic solvents while CTS dissolves readily in dilute acidic solutions [19]. Aqueous acid solutions with pH below 6.0 have been found to be the best solvents for CTS. Such acids include acetic acid, hydrochloric acid, nitric acid and formic acid. However, sulfuric and phosphoric acids are not suitable solvents for CTS as it is insoluble in them [17]. Numerous articles have reviewed the application of chitosan and its derivatives in removing contaminants from water samples, wastewaters, dye compounds and heavy metals [20–24]. However, to date, there is limited number of literature on the successful simultaneous removal of mycotoxin with CTS as adsorbent [9,25,26].

To the best our knowledge, this is the first study on the simultaneous removal of 11 toxic mycotoxins in PKC using CTS.

#### **2. Results and Discussion**
