Biodiversity as a tool for waste phycoremediation and biomass production

摘要

Over the past 20 years, plants have been used to an increasing extent in various environments for mitigating pollutant concentrations in contaminated sites (soils or waters) and for producing biodiesel. However, because plant growth rates and biomass yields are low and because a considerable amount of water and large surface area are required, intensive cultivation of microalgae has been proposed as an alternative method for phycoremediation and producing bio-energy (Dismukes et al. 2008; Rawat et al. 2011). However, mass cultivation of microalgae in open systems (and, to a certain extent, in closed systems) is subject to strong competition (from local microalgal communities when single species microalgal biopro-cesses are considered) and predation and are particularly sensitive to sudden changes in environmental conditions (light, temperature and nutrient availability). Such factors may contribute to the rapid collapse of the microalgae culture. The use of indigenous microalgae species for local intensive production, better adapted to local climatic conditions, may reduce potential competition to some extent without risk of the culture becoming noxious or invasive, as claimed recently by Wilkie et al. (2011). However, the stability of microalgal productivity in a single species culture is doubtful when cultures are supplied with heterogeneous wastewaters containing various organic and inorganic compounds, some of which are toxic, together with their own microbial communities feeding on the waste.