Факторы, влияющие на концентрацию с-фикоцианина в клетках Limnospira (Spirulina) Platensis при различных сроках хранения в обезвоженном состоянии

Abstract

Limnospira (Spirulina) platensis, has a high nutritional value, it contains up to 70 % protein, carotenoids, vitamins B, E, other nutrients and minerals. Optimal storage of cyanobacteria is achieved by drying, and in this form the biomass does not lose its useful properties for a long time. In addition, the cells retain viability by going into an anhydrobiosis state, which is crucial for preserving the biodiversity of cyanoprokaryotes and microalgae in storage. Among the biochemical components of L. platensis, of particular interest is the pigment C-phicocyanin (C-phc), which has antioxidant, immunomodulatory and cancer-protective properties and is part of the photosynthetic pigment complexes of cyanobacteria. The aim of this work was to determine the content of C-phc  in samples of L. platensis preserved in the state of anhydrobiosis from 1 to 19 years and to identify the main factors affecting the decrease in the concentration of the pigment. Standard (biochemical and optical) methods of L. platensis biomass studies and microscopic methods for the control of associated microflora were used in this work. The maximum amount of C-phc was obtained at a temperature (T) of 30 °C (5.6 % and 3.4 %, respectively, for the 2nd and 12th years of storage). Dehydration at higher temperatures (50 ºC and 60 ºC) led to a decrease in pigment content, until its complete disintegration (1.9 % and 0.54 %, respectively for 2nd and 12th year of storage). No clear correlation between the level of C-phc concentration and residual moisture content (RM) was found, however, in 23 % of samples at high dehydration temperatures increased residual moisture content (12 – 16 %) was found. Compared to the 2nd year of storage, the dominance of destroyed trichomes in long-term storage (19 years) and massive development of associated bacteria were revealed. A decrease in the concentration of C-phc and a decrease in the variability of the indicator with increasing storage time of the samples were found; probably, storage period, along with temperature and residual humidity, influenced the decrease in the concentration of pigment. Probably, the content of C-phc can be considered as an indicator of L. platensis cell viability. When transferring cyanobacteria to the state of anhydrobiosis the most optimal is: dehydration at temperature 30 ºC, 9 – 11 % RM and storage of samples not more than 2 years. The obtained results may be useful for preservation of algocultures and cyanobacteria in anhydrobiosis collections in order to preserve biodiversity and obtain biomass rich in C-phc.

Keywords: cyanobacteria, microalgae, anhydrobiosis, dehydration, residual moisture, temperature, storage period