Abstract
Industrial microalgae, as a big family of promising producers of renewable biomass
feedstock, have been commercially exploited for functional food, living feed and feed additives,
high-value chemicals in nutraceuticals, cosmeceuticals, and chemical reagents. Recently, microalgae
have also been considered as a group that might play an important role in biofuel development and
environmental protection. Almost all current products of industrial microalgae are derived from
their biomass; however, large amounts of spent cell-free media are available from mass cultivation
that is mostly unexploited. In this contribution we discuss that these media, which may contain
a remarkable diversity of bioactive substances are worthy to be recovered for further use. Obviously,
the extracellular metabolites from industrial microalgae have long been neglected in the development
of production methods for valuable metabolites. With the advances in the last ten years, more and
more structures and properties from extracellular metabolites have been identified, and the potential
utilization over wide fields is attracting attention. Some of these extracellular metabolites can be
potentially used as drugs, antioxidants, growth regulators or metal chelators. The purpose of this
review is to provide an overview of the known extracellular metabolites from industrial microalgae
which might be of commercial interest. The attention mainly focuses on the reports of extracellular
bioactive metabolites and their potential application in biotechnology.
