Steam explosion as a green method to treat animal waste: A mini-review

Abstract

Steam explosion (SE) technology has been widely used to treat lignocellulosic materials for a long time. However, the investigation regarding SE applied for animal waste treatment is limited. With an increase in the demand for and consumption of meat, the annual production of various animal by-products, such as animal keratinous waste and bone waste, is also increasing in slaughterhouses. Therefore, a green method for disposing of these by-products is needed. In this article, the current SE devices, together with their characteristics and applications in wool, feather, hoof, and animal bone, are reviewed systematically. Different SE conditions result in the production of varying final products, from which keratin and other constituents (protein, lipid, or carbohydrate) can be extracted. Additionally, under proper conditions, SE can induce the liquefaction of animal wastes, such as porcine hoof shells, bovine bone, and even the whole chicken carcass. The advantages and limitations of the SE technology employed for treating animal waste were analyzed. Simultaneously, the reasons SE is used to treat animal keratin and bone wastes were also discussed. This review highlights the potential application of SE technology in efficiently liquefying animal wastes for bio-safety disposal and cleaner production.