Danko Y1 Havryliuk O2 Hovorukha V2 Tashyrev O2 Yastremska L.1

1National Aviation University,

Faculty of environmental safety, engineering and technology, Department of biotechnology

2D.K. Zabolotny Institute of Microbiology and Virology of the NAS of Ukraine,

Department of extremophilic microorganism’s biology

e-mail: yaninanina2000@gmail.com

The search of alternative sources and ways to obtain industrially promising materials is of considerable interest for scientists worldwide. Chitin is one of such materials. It has a wide range of applications in the medical, food, chemical, and pharmaceutical industries. The shells of crustaceans, squid, biomass of mycelial fungi, arthropods, etc. are the most promising sources of chitin. In contrast to chemical methods (treatment by mineral acids and alkalis), biological methods of chitin deproteinization are promising and cost-profitable.

The aim of the work was to determine the effectiveness of microbial destruction of arthropod tissues to obtain purified chitin.

Dried arthropod tissues were used for the investigation. The tissues were thoroughly grinded to a powder before destruction. Specialized microbiome of proteolytic bacteria of digested sludge of methanetank was used as destructors of protein polymers. Cultivation was conducted in mineral medium at the temperature 30°C during 4 month. Crushed arthropod tissue was used as a source of carbon and energy. Colorimetric and potentiometric methods were used for pH and redox potential measurement. The concentration of soluble organic compounds was determined by the permanganate method. The efficiency of destruction was evaluated by the change in the concentration of organic compounds, as well as by the difference between the dry masses of arthropod tissues before and after microbial destruction.

Microbial destruction of arthropod tissues was shown. The initial concentration of soluble organic compounds (SOC) after addition of tissues was 734 ppm. It is obvious that the hydrolysis of solid protein compounds (contained in the arthropod tissues) has occurred during the destruction process. This was evidenced by the increase in the concentration of SOC from 734 ppm to 1850 ppm in 14 days.

However, the concentration of organic compounds was only 11 ppm after 27 days of destruction. This indicates that the main process of destruction lasted 27 days. Repeated destruction cycles were performed after two and four months from the start of the experiment. Due to this, the concentration of organic compounds was reduced from 134 to 35 ppm (4 months of cultivation). The efficiency of destruction was 91%.

Thus, the obtained data indicate that the specialized microbiome of proteolytic bacteria provides hydrolysis of solid arthropoda tissues. This was evidenced by the accumulation of SOC in the culture liquid during first 14 days. After that, accumulated SOC were destroyed to the final compounds – CO2 and H2O by microorganisms. It is obviously that the efficiency of destruction of arthropod tissues can be increased by the optimization of such microbial method. Optimization of the method will allow replacing expensive industrial methods of chitin purification by eco-friendly and cost profitable microbial technologies.