The Effect of Salinity on Growth, Dry Weight and Lipid Content of the Mixed Microalgae Culture Isolated from Glagah as Biodiesel Substrate

Abstract

Abstract:Microalgae use photosynthesis to convert solar energy into chemical energy, such as lipid and they can be a replacement for oil-based fuels. They are among the fastest growing plants in the world, and about 50% of their weight is oil. This lipid oil can be used to make biodiesel. Unfortunately, there are only some of potential strains isolated from Indonesia and most of the biodiesel productions are usually using a single strain. Then, although they are rich of oils, their biomass productivity is still low. Salinity treatment can be used to increase their biomass as well as their lipid content. Therefore, the research aim was to study the effect of salinity on the growth, dry weight and lipid content of mixed microalgae isolated from Glagah, Yogyakarta. The mixed microalgae were cultured in 3NBBM medium with different salinities or types of water (sea water, brackish water, and fresh water). The cultures were incubated at light intensity 3,000 lux under dark:light exposure of 12:12 h for 7 days. The number of cells was counted every 24 h with a Haemocytometer, and the biomass was calculated based on the dry weight. The lipid content was measured on days 0, 3, and 7 using NR (Nile Red) staining, and then the amount of lipid was analyzed using a fluorescence microscope and measured with CellProfiler 2.0 software. The highest dry weight and lipid content were found in seawater medium, they accounted for 3.42 mg/mL and 13.58% at day 7, respectively. Whereas, the highest number of cells was found in freshwater medium, this was 9.8 × 10 6 cells/mL.

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“…is cultivated in an F/2 medium with a salinity of 30%. When the cultures are mixed, osmotic stress will occur in Glagah Consortium cells, increasing carbon storage in cell walls, such as cellulose and hemicellulose (Suyono et al, 2015). No significant differences were observed between Glagah Consortium control and the mixed samples.…”

“…Harvesting of microalgae was done at the end of exponential growth, where secondary metabolite production is abundant (Cruz et al, 2020;Lutfi et al, 2019;Suyono et al, 2015). Mixing the Glagah Consortium with Anabaena sp.…”

“…G l a g a h C o n s o r t i u m i s a l o c a l microalgae strain isolated from Glagah Beach, Yogyakarta, Indonesia, which contains 6 different species of microalgae and a symbiotic relationship with bacteria (Suyono et al, 2015(Suyono et al, , 2018. This strain has the potential to be used as a source of biofuel due to its high lipid content, reaching up to 13.58% and a lower ratio of polyunsaturated fatty acids (Sadaatkhah et al, 2020;Suyono et al, 2016).…”

Enhacment of biomass, carbohydrates, lipids, and proteins content using co-culture of Glagah consortium and Lipomyces starkeyi

“…Lipids produced by microalgae are considered the most valuable components of biomass that can be used in biodiesel production (Aresta and Dibendettp, 2019). Indigenous microalgae from Glagah Beach can produce biodiesel which is quite high (Suyono et al, 2015). L. starkeyi is yeast which is a good candidate for SCO (Single Cell Oils) because its dry cells can accumulate as much as 70% of SCO (Bonturi et al, 2015).…”

“…Lipids are a form of microalgae cell osmoprotectant to prevent intracellular osmolarity imbalances that can harm microalgae cells. As a local strain, the Glagah consortium has the potential to produce higher lipids as biodiesel because the environmental conditions are adequate for microalgae to grow faster with higher biomass (Suyono et al, 2015). Microalgae biomass comprises various organic groups such as carbohydrates, proteins, and lipids.…”