Heterotrophic and Photoautotrophic Media Optimization Using Response Surface Methodology for the Novel Microalga Chlorococcum amblystomatis

Abstract

The nutritional requirements of novel microalgal strains are key for their effective cultivation and metabolite content. Therefore, the optimization of heterotrophic and photoautotrophic culture media is crucial for novel Chlorococcum amblystomatis growth. Heterotrophic and photoautotrophic biomass samples were characterized to identify the differences between their heterotrophic and photoautotrophic biomass composition and their biotechnological potential. Media optimization through surface response methodology led to 44.9 and 51.2% increments in C. amblystomatis-specific growth rates under heterotrophic and photoautotrophic growth, respectively. This microalga registered high protein content (61.49–73.45% dry weight), with the highest value being observed in the optimized photoautotrophic growth medium. The lipid fraction mainly constituted polyunsaturated fatty acids, ranging from 44.47 to 51.41% for total fatty acids (TFA) in cells under heterotrophy. However, these contents became significantly higher (70.46–72.82% TFA) in cultures cultivated under photoautotrophy. An interesting carotenoids content was achieved in the cultures grown in optimized photoautotrophic medium: 5.84 mg·g−1 β-carotene, 5.27 mg·g−1 lutein, 3.66 mg·g−1 neoxanthin, and 0.75 mg·g−1 violaxanthin. Therefore, C. amblystomatis demonstrated an interesting growth performance and nutritional profile for food supplements and feed products that might contribute to meeting the world’s nutritional demand.

Scenedesmus rubescens Heterotrophic Production Strategies for Added Value Biomass

“…Comparing the composition of both media, 5× concentrated Bold's medium had a higher concentration of most nutrients, particularly nitrogen and phosphate, which could influence Scenedesmus growth as it also affected the growth of Chlorococcum sp. and S. acuminatus in other published studies [5,6].…”

“…Microalgae can be produced under autotrophic, mixotrophic, and heterotrophic conditions. However, only a few microalgae, such as Scenedesmus sp., Chlorococcum sp., Chlorella sp., and Chlamydomonas sp., grow heterotrophically [5][6][7][8]. Under these conditions, microalgae use organic substrates both as energy and as carbon sources [9], and production occurs in closed-stirred reactors, such as industrial fermenters [9], and in axenic conditions [10].…”

Comparison of the Regenerative Metabolic Efficiency of Lipid Extracts from Microalgae Nannochloropsis oceanica and Chlorococcum amblystomatis on Fibroblasts

“…Moreover, it was found that astaxanthin, among others, participates in the activation and effectiveness of the Nrf2 transcription factor [ 84 , 85 ], which corresponds to these results. The antioxidant and anti-inflammatory effects are also supported by β-carotene and chlorophyll α and β present in the tested microalgae [ 30 , 86 ].…”

“…However, C.a. has a stronger effect, significantly increasing the levels of both phospholipids and free EPA and DHA [ 26 , 27 , 30 ]. It can also be suggested that the lipophilic microenvironment created in the culture medium by used microalgae may promote the biosynthesis of both free and phospholipid PUFAs in fibroblasts.…”

“…In addition to these fatty acids, the microalgae C.a. is characterized by a high content of chlorophyll α and β [ 30 ], which allows the production of preparations supporting the treatment of cardiovascular diseases and complications [ 31 ]. Additionally, it has been shown that chlorophyll, in cooperation with lutein, also presents in this microalgae; these are strong antioxidants which additionally feed the body, detoxify the body, and also support executive units and maintain the hormonal balance of the human body by binding and removing certain endocrine-disrupting substances [ 27 , 30 , 31 ].…”