Highlight Research Extract N-hexane of salina contains alkaloids, steroids, triterpenoids, and phenols Extract Ethyl Acetate of salina contains alkaloids, steroids, triterpenoids, phenols, flavonoid, and saponins Extract Methanol of salina contains alkaloids, steroids, triterpenoids, phenols, flavonoid, and saponins 24- hours LC50 value of the n-hexane extract salina was 276 ppm, the ethyl acetate extract was 673 ppm and the methanol extract was 811 ppm. All of the three extracts were included in toxic category   Abstract Microalgae are single celled microorganisms as the primary producers in the water food cycle. Microalgae bioactive compounds was estimated to be 10 times more diverse than compounds produced by land plants. Microalgae use nutrients more efficiently to grow, metabolize, and produce chemical compounds. Dunaliella salina is a type of chlorophyte microalgae with a lot of potential to be used in various fields. This study aimed to determine the phytochemical compound content and the value of lethal toxicity (24-hour LC50) in microalgae D. salina extract with different solvents. The multistage maceration method uses n-hexane, ethyl acetate, and methanol to extract samples. Phytochemical screening uses reagents according to the content of secondary metabolites. The Brine Shrimp Lethality Test method is used to test toxicity. The extracts were tested by using 10 Artemia salina against five concentrations, namely 0, 1, 10, 100, and 1000 ppm. Toxicity data were processed through probit analysis to get the 24-hour LC50 value. The results showed that alkaloids, steroids, triterpenoids, and phenols were found in the methanol, ethyl acetate, and n-hexane extracts. Saponin were found in the methanolic extracts. Flavonoid were found in the methanol and ethyl acetate extracts. The 24-hour LC50 value of the n-hexane extract was 276 ppm, the methanol extract was 811 ppm, and ethyl acetate extract was 673 ppm. The three extracts were included in toxic category. Extracts of microalgae D. salina have plenty secondary metabolite, that can be used in various fields and holds the potential as an anticancer.

Highlight ResearchThe author mentioned 2 highlights from their results research  Nano-chitosan has the best susceptibility to bacterial strains of E. coli, S. enteritidis, L. monocytogenes, B. cereus and S. aureus.Nano-chitosan showed higher degree of inhibition than that done by chitosan. AbstractThe COVID-19 pandemic has impacted the fisheries sector, a decline in exports and fishermen's income caused by the disconnection of the marketing chain due to lockdown implementation in several export destination countries. Fish is a source of protein and as perishable goods, it experiences quality damage due to spoilage, commonly caused by hampered distribution of catches. Natural preservatives are needed to preserve catch so it won’t get spoiled and can be accepted by consumers in suitable conditions for consumption. This study aims to evaluate the particle size of nano-chitosan and determine the effectiveness of nano-chitosan spray with different concentrations as a natural preservative in caught fish. This research method begins with making chitosan through 3 stages: demineralization, deproteination, and deacetylation. Chitosan was made into nano-chitosan with various concentrations of 3:1, 4:1, and 5:1 using ionic gelation. Nano-chitosan underwent several tests, including PSA, antibacterial activity by disc diffusion, organoleptic, and the effectiveness of preservatives. Antibacterial activity of nano-chitosan was able to inhibit Bacillus subtilis at three different concentrations, the potential to inhibit Escherichia coli was optimal at 5:1 treatment. The effectiveness of nano-chitosan preservative bacteria inhibition at three different concentrations proved to be sufficient to be used to extend shelf life and ensure the safety and quality of fishery products. The best concentration of nano-chitosan was 3:1 treatment. Nano-chitosan spray from crab shell waste has good antibacterial activity and preservative effectiveness. It could serve as an antibacterial agent and natural preservative for fishery products during the COVID-19 pandemic.