Techniques to analyze microbial diversity during composting—A mini review

One of the most versatile and remunerative techniques for handling biodegradable solid wastes is composting. Composting refers to aerobic degradation of organic material and is one of the main waste treatment methods used for treating separated organic waste. Microbes play a key role as degraders during the composting-process and microbiology of composting has been studied for decades. Microorganisms participating in the self-heating phase of composting material could be characterized through cultural enumeration of microbe populations on one hand and, on the other hand, by a molecular investigation of the microbial community by restriction enzyme analyses of a clone library of bacterial 16S rRNA genes. It is well known that, with the traditional culture-based methods, only a small fraction (below 1%) of the species in a sample is normally detected. Furthermore, microbes can be mutualistic, symbiotic and parasitic and for these microbes growth conditions are hard to mimic. Use of polymerase chain reaction (PCR) and DGGE (denaturing gradient gel electrophoresis) have substantially enhanced the charm of the independent methods. The present review reveals the lack of sensitivity and specificity of culture dependent methods and preference of culture independent approach in microbial ecology to study the microbial diversity in a complex process of solid waste composting.