Kappaphycus alvarezii is type of red seaweed that widely cultivated in Indonesia. K. alvarezii contains phycobiliproteins mainly phycoerythrin which is commonly used as natural dyes in food and cosmetics, fluorescent, and analytical reagents. Phycoerythrin is generally extracted from red seaweed using buffer phosphate with freeze thawing process. The purpose of this study was to determine the effect of extraction time using ultrasonic waves on the characteristics of phycoerythrin. The maximum absorbance was formed at a wavelength of 499, 534, and 564 nm. Ultrasonic extraction treatment for 30 min and precipitation 60% ammonium sulfate were the best treatments, which had a pigment concentration of 1.9102 mg/mL, purity index 0.8311, and protein concentration of 0.5206 mg/mL. The antioxidant activity possessed by the phycoerythrin pigment is categorized as strong to very strong.

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This study analyzes the spatial autocorrelation of economic growth and labor and the factors that influence economic growth between districts/cities in the Southern Sumatra region. The data used is secondary data sourced from the Bureau of Central Statistics. The method used is a quantitative approach by applying the Moran Index, LISA, and multiple regression models. This study shows that the spatial autocorrelation of economic growth did not occur in the Southern Sumatra region. Meanwhile, the spatial autocorrelation of labor occurs in this region so that it affects each other. This study’s finding that jointly the variables of potential market indicator, fixed capital investment, human capital, and labor force participation rate have a significant effect on GRDP. Likewise, partially the potential market indicators, capital fixed asset investment, human resources, and labor force participation rates have a positive and significant effect on GRDP.