Diversity of Psychrophilic Colonies and Their Biotechnological Potential

Abstract

Psychrophilic bacteria are a large group of microorganisms that prevail in low-temperature ecosystems. Psychrophilic bacteria have undergone a number of adaptations that help them exist in such conditions. One of such adaptations is the use of enzymes with a high specific activity at low temperatures. Such enzymes are usually called “cold-active.” These enzymes have potential applications in biotechnology and industry. In our review, we considered individual genera of psychrophilic bacteria, current global trends in the study of cold-active enzymes, their applications, and place in industrial biotechnology. Thus, the main goal of this study was to explore the diversity of psychrophilic bacteria, as well as opportunities of their application in biotechnology. The natural ecological sites of psychrophiles are numerous and varied. Psychrophiles form a permanent microflora of eternal cold regions, polar regions and oceans. Bacteria belonging to this group are found in soil, water or associated with plants and animals. An important site for psychrophilic microorganisms is a low-temperature water reservoir. At present, many new genera of psychrophiles and psychrotrophs have been derived from the bottom sediments and sea waters of the Arctic and Antarctic and described. Psychrophilic microorganisms are found in caves and in ancient ice crystal structures. The latter testifies to the very possibility of the super-long anabiosis phenomenon, as well as vital capacity preservation without division for a long period of time. Psychrophiles do not have a single form, they belong to at least several phylogenetic groups. Psychrophilic forms are found among the representatives of a large number of genera. There are no common physiological and biochemical parameters typical of psychrophilic bacteria. They comprise rods, cocci, vibrios, gram-negative and gram-positive bacteria, bacteria that produce and do not produce spores, strict aerobes, facultative and strict anaerobes. We lay greater emphasis on the diversity of psychrophilic bacteria capable of producing industrially important enzymes. The review considers bacteria belonging to the genera Vibrio and Aliivibrio, Pseudomonas, Achromobacter, Arthrobacter, Pseudoalteromonas, Bacillus, Clostridium, Micrococcus, Psychrobacter, Psychromonas, Flavobacterium, and psychrophilic methanotrophic microorganisms. These bacteria enzymes are used in agriculture, biotechnology, pharmaceuticals and household chemicals, as well as other sectors of the national economy. Psychrophilic bacteria produce a chemical compound that can be used in medicine. For example, Pseudomonas antarctica contains a cluster of genes encoding microcin B, R-type pyocins, adenosylcobalamin, and pyrroloquinoline quinone. Thus, P. antarctica has antibiotic activity. Psychrobacter proteolyticus also has an antineoplastic action and secrets an extracellular cold-adapted metalloproteinase being able to inhibit the space-occupying process. Cold-active metalloproteinases are also widely used as detergents, in currying, food sector and molecular biology. The immunogenic Pal conformable protein was derived from the psychrophilic strain of The representatives of the genus Arthrobacter capable of metabolizing diuron and petroleum products have an important property. A. agilis produces a red pigment, a bacterioruberin-type carotenoid being interesting as an antioxidant. A. psychrochitiniphilus is promising for cleaning water areas, oil-polluted coastlines, as it decomposes oil and petroleum products. Flavobacterium limicola is a potential source of cold-active protease. This bacterium is characterized by an increase in protease secretion as temperature decreases. Thus, F. limicola can be used in environmental biotransformations and bioremediations. The psychrophilic bacteria of the genus Bacillus are the participants of active studies. Their cold-active enzymes have a high potential in various areas of biomedicine, immunology, decontamination, and various industrial applications. The antifreeze proteins of psychrophilic Clostridia are considered a promising biotechnological product for use in medicine, food, beauty products, fuel, and other industries. This study reviews literary sources and indicates that at present obligate and facultative psychrophiles (psychrotrophs) and their cold-active enzymes are of scientific interest throughout the world. A significant part of the research is focused on a general understanding of the distribution of psychrophilic bacteria and a local study of enzymatic activity. A further study of psychrophilic microorganisms producing enzymes at low temperatures will reveal new ways for the development of biotechnologies in various sectors of the national economy. The paper contains 94 References. The Authors declare no conflict of interest.