Lipid accumulation patterns and role of different fatty acid types towards mitigating salinity fluctuations in Chlorella vulgaris

Abstract

Mangrove-dwelling microalgae are well adapted to frequent encounters of salinity fluctuations across their various growth phases but are lesser studied. The current study explored the adaptive changes (in terms of biomass, oil content and fatty acid composition) of mangrove-isolated C. vulgaris UMT-M1 cultured under different salinity levels (5, 10, 15, 20, 30 ppt). The highest total oil content was recorded in cultures at 15 ppt salinity (63.5% of dry weight) with uncompromised biomass productivity, thus highlighting the ‘trigger-threshold’ for oil accumulation in C. vulgaris UMT-M1. Subsequently, C. vulgaris UMT-M1 was further assessed across different growth phases under 15 ppt. The various short, medium and long-chain fatty acids (particularly C20:0), coupled with a high level of C18:3n3 PUFA reported at early exponential phase represents their physiological importance during rapid cell growth. Accumulation of C18:1 and C18:2 at stationary growth phase across all salinities was seen as cells accumulating substrate for C18:3n3 should the cells anticipate a move from stationary phase into new growth phase. This study sheds some light on the possibility of ‘triggered’ oil accumulation with uninterrupted growth and the participation of various fatty acid types upon salinity mitigation in a mangrove-dwelling microalgae.

Fatty Acid Profile of Microalgal Oils as a Criterion for Selection of the Best Feedstock for Biodiesel Production

“…In microalgal biomass cultivated in culture medium with complete suggested nutrient rate (100% F/2), palmitic acid (16:0), oleic acid (18:1), linoleic acid (18:2) and linolenic acid (C18:3 n-3) were dominant in the profile, but in different quantities for each strain. Due to environmental stress, fatty acid composition changes [79] which was also observed in this study. A 50% reduction of the dose for all medium components increased palmitic acid content for all strains, oleic acid content for C. fusca and O. submarina, and linoleic acid for C. vulgaris and C. fusca.…”

An appraisal of the variable response of microalgal lipids to culture salinity

“…This aspect has hardly been addressed in the studies carried out to date, although some authors have claimed its relevance. 5,43,44 It has been shown that microalgal adaptation to salt stress involves an intense metabolic activity demanding high energy. 45 To optimize production systems, it is therefore necessary to identify the specific effects that salinity directly exerts on the lipid content in microalgae during their active growth.…”

“…Production of freshwater microalgae at higher salinity is possible thanks to the availability of several salttolerant species. [2][3][4][5] Microalgal production in environments of variable salinity may be even more feasible if not only estuarine species…”

Biotechnological peculiarities of microalgae chlorella production and use in poultry

“…The interest in this one can be explained by its biochemical characteristics, which make it attractive not only in poultry farming but also in animal husbandry, since it replenishes the protein deficit with all essential amino acids and the vitamin spectrum, including fat-soluble ones, as well as microand macro elements in a bioavailable form. Microalgae can synthesize a natural antibiotic called "chlorellin" which is active against Gram-positive and Gram-negative microorganisms [2,3]. The geographical features of the Russian Federation and other countries of the world are not always able to provide the available livestock with the necessary amount of fodder units at the expense of regional fodder raw materials.…”

“…The authors of the developments, solving the specified problem, use such methods as modernization of technological equipment, optimization of nutrient medium, as well as biophysical methods of treatment aimed at increasing the yield of the target product and reducing the cost of production technology of microalgae. The chemical composition of the chlorella suspension depends on the composition of the nutrient medium: a medium rich in nitrogen allows the accumulation of protein, in another way, a lack of nitrogen leads to an accumulation of lipids and carbohydrates [2,3]. Optimization of cultivation conditions of microalgae will produce a suspension with a biochemical composition satisfying the needs of poultry in nutrients.…”