From biogas energy, biotechnology to new agriculture

Abstract

Agriculture in the 21st Century is facing new challenges and transformation according to five general trends: commercialisation, internationalisation, science and technology, environment and energy production. In this laboratory, a series of research, development and commercialisation of biogas and enzyme technologies reflect these trends. Anaerobic digestion is a microbial process that converts organic waste into biogas, containing 60–70% methane. A simple thermophilic anaerobic digestion (TAnD) system for poultry manure was developed from the lab to the farm. TAnD at 50 to 60°C produces biogas at high rates and, as a result, the process is efficient and the digester is a compact unit. A pilot plug-flow TAnD was first constructed and operated at NCSU research farm. Multiple benefits of the system were demonstrated. Supported by UNDP, a TAnD to process five tons of manure daily (from 50,000 hens) was constructed in China and has been operating for 20 years. Large scale digesters processing hundreds of tons of manure daily are increasingly popular in China and Europe. Biogas from large digesters can be a significant source of energy to generate electricity or to fuel transportation. Beyond energy production, the digester is a rich source of biomaterials. A feather-degrading bacterium was discovered and isolated from TAnD, and its keratinase enzyme and the gene encoding for the enzyme were subsequently isolated. Genetic manipulation for over-expression and up-scale fermentation have now made the industrial production of the enzyme possible. As a heat-stable protease, the keratinase was found to be useful in processing feather meal, in enhancing feed digestibility and was able to degrade prion proteins (implicated as the disease vector in bovine spongiform encephalopathy).