Bioluminescent Activity Preservation of Photobacterium phosphoreum Using Microbial Exopolysaccharide Compositions

Biosensorics is a new branch of analytical biotechnology, one of the main directions of which is the development of electrochemical biosensors. Microorganisms capable of bioluminescence are often used in biosensor systems. Such microorganisms include marine bioluminescent bacteria Aliivibrio ficsheri, Vibrio campbellii, Vibrio harveyi, Photobacterium phosphoreum, etc. Since these marine microorganisms require rather complex environments for their cultivation and maintenance of the luminescence process, the development of an environment for improving the bioluminescence process is extremely urgent. In the course of many years of research, employees of the Department of Phytopathogenic Bacteria and other departments of the Zabolotny Institute of Microbiology and Virology of Ukrainian National Academy of Sciences have developed a number of gel preparations using copolymer EPAA (based on the microbial exopolysaccharide (EPS) xanthan and polyacrylamide) and lipcogenic compositions based on it. In particular, gel preparations of Pantoea agglomérans, and Bradyrhizobium jaronicum, Bacillus thuringiensis have been developed. The use of these compositions made it possible to improve and prolong the storage titers of these drugs and the output of certain metabolites. Considering this, the aim of our research was the development of a gel medium using EPS, copolymer EPAA, and gel compositions based on it, which could ensure long-term and high- luminescence of Photobacterium phosphoreum bacteria. Methods. Classic microbiological and static methods were used in the research. Results. It is shown that the optimal medium for the cultivation of P. phosphoreum B-7071 based on the preservation of luminescence intensity indicators used in microbial biosensors is a mixture of 2% lipocogenic composition D (70% EPAA + 30% EPS–xanthan) and 3% NaCl solution in a ratio of 1:1 for 50% occupancy of the polypropylene container. Conclusions. The results obtained correlate with the data of the literature since it is shown that, like in the experiments with P. phosphoreum B-7071, the addition of EPAA, EPS, and/or lipcogenic compositions based on them to the culture medium of microorganisms has a positive effect on the processes of growth and development of this strain as well as their synthesis of separate groups of metabolites associated with bioluminescence.