Industrial and Energy Uses of Animal By-products, past and Future

This chapter addresses the application of rendered products to the production of energy and other industrial uses. The high volume of rendered product generated precludes investigation into most high value/low volume markets. Future regulation relating to biosecurity and environmental protection has the potential to restrict traditional market access for rendered co-products. It is essential to develop product applications that demand large volumes of raw material to ensure the viability of the rendering industry. Historically, tallow has had much wider energy and industrial application than protein-based meals. Fertilizer and soil conditioners were a minor avenue for animal by-products whilst there was widespread and profitable use of protein-based meals in the feed and food sector. Rendered products have traditionally been used as a source of digestible protein, nutrients, and energy in the feed and food industries. There are physical/chemical methods for transforming that intrinsic energy value into a commercial fuel. Tallow-derived biodiesel is the most obvious alternative use for animal by-products. Use of protein meals as energy sources is technically feasible using pyrolysis, anaerobic digestion, and incineration/co-firing, but may have economic limitations. The potential for industrial uses of protein meals is limited. Proteins are a potential raw material for bio-based plastics and carton board adhesives. Natural forms of hydroxyapatite, found in high-density leg bones of cattle, sheep, and goats, has application as an absorbent, a catalyst, a dental substrate, and as a bone substitute. If these industrial applications are to be realized there are several technical and economic hurdles to overcome.