Another interesting feature of bioflocs to further investigate with
respect to biocontrol effects is the capability to accumulate the bacterial
storage compound poly-β-hydroxybutyrate (PHB). PHB and PHBaccumulating
bacteria have been shown before to protect different
aquaculture animals from bacterial infections (De Schryver et al.,
2010; Defoirdt et al., 2007; Dinh et al., 2010; Halet et al., 2007).
PHB-accumulating bacteria are present in bioflocs as we have measured
PHB levels in bioflocs of between 0.5 and 18% of the dry matter
(Crab, 2010; De Schryver and Verstraete, 2009). The latter bioflocs
contain a sufficient PHB level to protect cultured animals from infection
by pathogenic bacteria