Cellulases from Psychrophilic and Psychrotrophic Microorganisms and their Potential Applications

Psychrophilic and psychrotrophic microorganisms are those that have the ability to grow at low temperatures and are widely distributed around the globe. They are catalytically active at 0–40 ˚C temperatures and a pH range of 4.5–7.0 and are found inhabiting soil, water, and food, which make up upto 86% of the total population. These microbes, when exposed to higher temperatures, disrupt transcription and translation processes and inactivate certain heat-sensitive enzymes, inhibiting cell division and causing distortion of cell morphology. Cold-adaptive cellulases derived from cold-adapted microorganisms, their catalytic mechanisms, molecular modification, and applications are of utmost importance in various fields. In addition, they have a beneficial role in bioconversion and also in the food and fermentation industries, which have an impact on sustainable agriculture. This chapter discusses cold-adaptation mechanisms in bacteria in terms of their cellular components, especially proteins and lipids, membrane fluidity, translation machinery, nutrient uptake, biodegrading enzymes, and adaptations at the molecular level, including changes in gene expression, the production of cold-adaptive enzymes, and the production of cryoprotectants, chaperones, and antifreeze proteins. Understanding all these mechanisms may offer greater insight into the proteins and enzymes that offer advantages as industrial candidates for commercial purposes.