Plant Production with Microalgal Biostimulants

In order to ensure food security worldwide in the face of current climate changes, a higher quality and quantity of crops are necessary to sustain the growing human population. By developing a sustainable circular economy and biorefinery approaches, we can move from a petroleum-based to a bio-based economy. Plant biostimulants have long been considered an important source of plant growth stimulants in agronomy and agro-industries with both macroalgae (seaweeds) and microalgae (microalgae). There has been extensive exploration of macroalgae biostimulants. A lack of research and high production costs have constrained the commercial implementation of microalgal biostimulants, despite their positive impacts on crop growth, development, and yield. The current knowledge on potential biostimulatory compounds from algae, key sources, and their quantitative information has been summarised in the present review. Our goal is to provide a brief overview of the potential for microalgal biostimulants to improve crop production and quality. A number of key aspects will be discussed, including the biostimulant effects caused by microalgae extracts as well as the feasibility and potential for co-cultures and co-application with other biostimulants and biofertilisers. This article will also discuss the current knowledge, recent developments, and achievements in extraction techniques, types of applications, and timings of applications. Ultimately, this review will highlight the potential of microalgal biostimulants for sustainable agricultural practices, the algal biochemical components that contribute to these traits, and, finally, bottlenecks and involved prospects in commercialising microalgal biostimulants.