Abstract
Bioremediation of aquaculture rearing water quality means degradation and reduction of unsafe waste substances such as toxic gases in a contaminated fish/shellfish farm by living organisms such as probiotics Bacillus spp. and Lactobacillus spp. Obviously, the biological treatment systems can have different requests including clean-up of contaminated rearing water of fish/shellfish farm, pond soil, sludge, and streams. The intensive aquaculture farming plus other human activities such as industrialization and urbanization all have increased the adverse effects such as environmental pollution and land degradation with a consequence in the reduction of productivity in aquaculture activity. Thus, bioremediation as an emerging, effective, and attractive management tool can treat and recover the environment, e.g. rearing water quality. This ecofriendly way of bioremediation has been applied worldwide, but with varying degrees of achievement. Application of Bacillus probiotics as bioremediatory tools in the rearing water of aquaculture species and soil of ponds, both in situ and ex situ, has been demonstrated as a strong manner of improving water quality and improving the growth performance and health status of the cultured fish/shellfish species. Therefore, bioremediation technology as a tool to degrade the pollutants is a profitable and environmentally friendly alternative, particularly where the removing of toxic gases such ammonia, nitrite, nitrate, and carbon dioxide are crucially harmful for the aquatic animal species. The available information concerning the application of Bacillus probiotics such B. subtilis and B. licheniformis in rearing water of fish and shrimp is attractive and promising due to the removal of unsafe toxic gases. Further, it has been shown that the application of Bacillus probiotics in the rearing water of aquatic animals can make a balance between the microorganisms in the water column or in the pond soil via a bacterial competition with a consequence in reducing the load of secondary pathogens. This chapter discusses the role of Bacillus probiotics as bioremediatory tools of rearing water of aquatic animal species.