291
axenic cultures) in the presence of tryptophan, which may indicate a faster uptake
of IAA in the coculture, hence its lower detection rate in the supernatant, or that the
tryptophan is being diverted into other pathways in the coculture (Labeeuw et al.
2016). However, tryptophan did increase the virulence of the bacteria on the algae,
indicating a role for tryptophan in the virulence of the bacteria (Labeeuw et al.
2016; Segev et al. 2016).
14.4 Possible Applications
Algae are grown commercially for a number of reasons, such as food supplements, for animal feedstocks, or biofuels (Spolaore et al. 2006; Chisti 2007;
Borowitzka 2013). Processing of the algae is an important step when the aim is
to collect valuable algal metabolites that can be used and/or sold for additional
profit, with harvesting and extraction being identified as one of the key bottlenecks currently (Greenwell et al. 2010). The current harvesting methods can be
problematic to scale up. One area that can be further investigated for improvement is flocculation, which often precedes other harvesting steps. The use of
bioflocculants—flocculent- producing bacteria—to coagulate the algae is an
attractive alternative to possibly toxic chemical flocculants (Oh et al. 2001;
Gutzeit et al. 2005; Wang et al. 2012; González-Fernández and Ballesteros
2013). Removing bacteria from algal species has been shown to drastically
reduce their flocculating ability, and further research in bacterial species
involved in algal flocculation would likely help improve harvesting (Lee et al.
2013; Ramanan et al. 2016).
This also demonstrates the importance of understanding the natural communities
present in algal systems and the possibilities in artificially creating a community
(‘synthetic ecology’) to increase the robustness and productivity of a commercial
algal system (Kazamia et al. 2012; Cho et al. 2015). Using more complex communities to produce biofuels could prevent crashes in the algal population from occurring, which causes delays in production and increases in cost. Understanding the
underlying interactions occurring in this community, as well as the bioactive molecules involved, will allow for control over the systems, including increased lipid
production (Keshtacher-Liebso et al. 1995; Lenneman et al. 2014; Cho et al. 2015).
Alternatively, addition of bacteria, or bioactive molecules that cause a change in the
symbiosis of the bacteria towards the algae, could allow for timed death within the
system. The impact and possibilities of bacteria in commercial systems have been
greatly underestimated, and only recently is the potential of bacteria starting to be
recognized (Wang et al. 2014a), although the role of the metabolites involved is still
greatly overlooked (Franz et al. 2013; Natrah et al. 2014; Demuez et al. 2015). The
addition of a single chemical compound instead of bacteria to induce a specific
desired change raises unique challenges and possibilities in biotechnological
advancement of algae.
14 Bioactive Small Molecules Mediate Microalgal-Bacterial Interactions
axenic cultures) in the presence of tryptophan, which may indicate a faster uptake
of IAA in the coculture, hence its lower detection rate in the supernatant, or that the
tryptophan is being diverted into other pathways in the coculture (Labeeuw et al.
2016). However, tryptophan did increase the virulence of the bacteria on the algae,
indicating a role for tryptophan in the virulence of the bacteria (Labeeuw et al.
2016; Segev et al. 2016).
14.4 Possible Applications
Algae are grown commercially for a number of reasons, such as food supplements, for animal feedstocks, or biofuels (Spolaore et al. 2006; Chisti 2007;
Borowitzka 2013). Processing of the algae is an important step when the aim is
to collect valuable algal metabolites that can be used and/or sold for additional
profit, with harvesting and extraction being identified as one of the key bottlenecks currently (Greenwell et al. 2010). The current harvesting methods can be
problematic to scale up. One area that can be further investigated for improvement is flocculation, which often precedes other harvesting steps. The use of
bioflocculants—flocculent- producing bacteria—to coagulate the algae is an
attractive alternative to possibly toxic chemical flocculants (Oh et al. 2001;
Gutzeit et al. 2005; Wang et al. 2012; González-Fernández and Ballesteros
2013). Removing bacteria from algal species has been shown to drastically
reduce their flocculating ability, and further research in bacterial species
involved in algal flocculation would likely help improve harvesting (Lee et al.
2013; Ramanan et al. 2016).
This also demonstrates the importance of understanding the natural communities
present in algal systems and the possibilities in artificially creating a community
(‘synthetic ecology’) to increase the robustness and productivity of a commercial
algal system (Kazamia et al. 2012; Cho et al. 2015). Using more complex communities to produce biofuels could prevent crashes in the algal population from occurring, which causes delays in production and increases in cost. Understanding the
underlying interactions occurring in this community, as well as the bioactive molecules involved, will allow for control over the systems, including increased lipid
production (Keshtacher-Liebso et al. 1995; Lenneman et al. 2014; Cho et al. 2015).
Alternatively, addition of bacteria, or bioactive molecules that cause a change in the
symbiosis of the bacteria towards the algae, could allow for timed death within the
system. The impact and possibilities of bacteria in commercial systems have been
greatly underestimated, and only recently is the potential of bacteria starting to be
recognized (Wang et al. 2014a), although the role of the metabolites involved is still
greatly overlooked (Franz et al. 2013; Natrah et al. 2014; Demuez et al. 2015). The
addition of a single chemical compound instead of bacteria to induce a specific
desired change raises unique challenges and possibilities in biotechnological
advancement of algae.
14 Bioactive Small Molecules Mediate Microalgal-Bacterial Interactions