Microorganisms living in the marine environment produce marine enzymes. These microorganisms live in environments characterized by extreme salinity, extreme pressure, or extreme temperature. Marine enzymes have concomitant properties, such as halostability or thermostability that have practical applications. Microbes isolated from harsh marine habitats produce enzymes such as gelatinase, caseinase, DNases, amylase, and lipase. These enzymes are thermostable and resistant to harsh conditions and a wide range of pH, making them appropriate for industrial applications. They can also be utilized in the food industry due to their mild operational conditions, amenableness in harsh conditions and specificity. This book is a valuable compilation of topics, ranging from the basic to the most complex advancements in the field of marine enzyme biotechnology. It will serve as a valuable source of reference for graduate and postgraduate students.