Chapter 3 Microbiology of the composting process

This chapter discusses the microbiology of the composting process. The biological cycling of nutrients is indispensable for life and is mediated through microorganisms. Biotransformation is a biological modification that alters the chemical structure of a substance. The decay of materials during composting follows the common biochemical pathways of any other degradation process. Generally, plant materials make up the highest amounts, while animal tissues or microbial components are only minor fractions of any mixture, but usually are the most nutrient-rich fractions. The degradation of organic compounds under natural conditions usually occurs in soils and sediments, on the soil surface, or in water bodies. In most cases, the decomposing substrates have physical contact with the degraded material or with an external matrix. Continuous composting processes may be regarded as a sequence of continuous cultures, each of them with their own physical, chemical, and biological properties and feedback effects. All of the microbial transformations of nitrogen occurring in nature also take place during composting, even if with different significance.