This chapter deals with the significance of soil microbes from an industrial
perspective. Soil microbes are the most diverse populations to exist on earth, and they
are known to have played a prominent role in the development of soil chemistry, soil
texture, and soil suitability to sustain plant life. The chapter deals with the significance
of cultural techniques for the isolation of desired microbial strains from the soil. The
importance of screening techniques for isolates is emphasized, wherein the potential
strains are tested for their physiological characteristics that are industrially beneficial.
A few criteria are mentioned for judging the soil isolate’s capability to become an
industrial strain. The difference between natural isolates and potential industrial strains
is discussed. Useful strains are categorized based on their ability to produce primary
and secondary metabolites with commercial applications in terms of economic,
agricultural, and environmental significance. Industrially important microbes are listed
with emphasis on the types of metabolites they produce and their applications.
Knowledge of metabolic pathways involved in metabolite production and their
regulation in terms of various feedback control systems are discussed. Strain
improvement and its role in improving industrial aspects of microbes are highlighted.
Bacillus sp. are given their due importance as the most diverse and dynamic forms of
bacteria, contributing immensely to our knowledge and being the most beneficial forms
of soil microbes. A few metabolites are discussed in detail, with emphasis given to
enzymes, microbial polymers, amino acids, solvents, organic acids, and antibiotics.
Microbial bioleaching mostly employs bacteria that could help in the recovery of
metals from low-grade ores, and industries based on biomining have shown a renewed
interest in this economically viable process.