Algal biofertilizers and plant growth stimulants for sustainable agricolture

Modern agricultural management is heavily dependent on the fertilizers for promotion of crop production, but the massive use of inorganic and chemical-based fertilizers currently available may be a serious threat to human health and environment. Fertilizer research is therefore focusing on shifting to the exploitation of microbes as a more ecofriendly approach for sustainable agriculture. The biotechnological toolbox contains microorganisms such as microalgae, cyanobacteria, endo- and ecto-mycorrhizal fungi, rhizobacteria, and others that are able to live in association with higher plants. This review article focuses on the research achievements on microalgae- and cyanobacteria-based plant biofertilizers and biostimulants in the agricultural applications. The challenges to commercializing these kinds of biofertilizers are also discussed.