Stepwise processing of Chlorella sorokiniana confers a plant biostimulant that saves 25 % of standard fertilizer

Modern technological approaches allow us to utilize microalgae in large scale industrial applications. Chlorella sp. has been widely utilized to produce food supplements and cosmetics, and also shows great potential for plant stimulation. For future production of plant biostimulants from microalgae, it is essential to extract bioactive compounds in a targeted manner as certain microalgal contents display plant inhibitory effects. Based on previous observations, we have designed a stepwise method for processing microalgal biomass that consists of maceration, homogenization and targeted hydrolysis. With this method, valuable bioactive properties of the C. sorokiniana extract were retained, while reducing unwanted plant inhibition. Moreover, 25 % of standard fertilizer was saved via application of the extract on tomato plants and significant increase of carbon and nitrogen metabolism was observed in the tomato leaves.