Bioaugmentation using salt-tolerant bacteria in a dual-stage process for high-salinity wastewater treatment: Performance, microbial community, and salt-tolerance mechanism

The recent increase in genomic data is revealing an unexpected perspective of gene loss as a pervasive source of genetic variation that can cause adaptive phenotypic diversity. This novel perspective of gene loss is raising new fundamental questions. How relevant has gene loss been in the divergence of phyla? How do genes change from being essential to dispensable and finally to being lost? Is gene loss mostly neutral, or can it be an effective way of adaptation? These questions are addressed, and insights are discussed from genomic studies of gene loss in populations and their relevance in evolutionary biology and biomedicine. Show more

Many industrial sectors are likely to generate highly saline wastewater: these include the agro-food, petroleum and leather industries. The discharge of such wastewater containing at the same time high salinity and high organic content without prior treatment is known to adversely affect the aquatic life, water potability and agriculture. Thus, legislation is becoming more stringent and the treatment of saline wastewater, both for organic matter and salt removal, is nowadays compulsory in many countries. Saline effluents are conventionally treated through physico-chemical means, as biological treatment is strongly inhibited by salts (mainly NaCl). However, the costs of physico-chemical treatments being particularly high, alternative systems for the treatment of organic matter are nowadays increasingly the focus of research. Most of such systems involve anaerobic or aerobic biological treatment. Even though biological treatment of carbonaceous, nitrogenous and phosphorous pollution has proved to be feasible at high salt concentrations, the performance obtained depends on a proper adaptation of the biomass or the use of halophilic organisms. Another major limit is related to the turbidity problems inherent in saline effluents. For this reason, the major need for research in the future will be the combination of physico-chemical/biological treatment of saline industrial effluents, with regard to the global treatment chain, in order to meet the regulations. Show more