Bioregeneration of spent activated carbon:Review of key factors and recent mathematical models of kinetics

The disposal of spent activated carbon(AC) will inevitably create secondary pollution. In overcoming this problem, the spent AC can be regenerated by means of biological approach. Bioregeneration is the phenomenon in which through the action of microorganisms, the adsorbed pollutants on the surface of the AC will be biodegraded and this enables further adsorption of pollutants to occur with time elapse. This review provides the challenges and perspectives for effective bioregeneration to occur in biological activated carbon(BAC)column. Owing to very few reported works on the bioregeneration rate in BAC column, emphasis is put forward on the recently developed models of bioregeneration kinetic in batch system. All in all, providing potential solutions in increasing the lifespan of AC and the enhancement of bioregeneration rate will definitely overcome the bottlenecks in spent AC bioregeneration.

Endosymbiotic pathogen-inhibitory gut bacteria in three Indian Major Carps under polyculture system: A step toward making a probiotics consortium

The gastrointestinal(GI)microbiome in fish plays significant roles in health and disease resistance.This investigation was accomplished to enumerate,characterize and identify the potential probiotic bacteria from three Indian Major Carps(IMCs),viz.,rohu(Labeo rohita),catla(Catla catla)and mrigal(Cirrhinus mrigala)using culture dependent methods.Altogether,105 pathogen-inhibitory bacteria(out of 1216 isolates)were detected from three IMCs by double layer assay.16S rRNA partial gene sequence analyses and BLAST search in the NCBI GenBank unveiled that 94.29%of the pathogen inhibitory bacteria were bacilli(99 strains)and Bacillus licheniformis by far the most common(28%).The primarily selected 27 pathogen-inhibitory strains(cumulative inhibition score≥13)produced extracellular enzymes,while 15 of them produced all the six exo-enzymes studied(amylase,protease,lipase,cellulase,phytase and xylanase).Gut stability of the strains became apparent by their ability to grow in fish mucus and tolerance to diluted bile-juice.Finally,14 strains were noticed asγ-hemolytic and susceptible to the commonly used antibiotics.Further,intra-peritoneal injection withγ-hemolytic strains did not induce any pathological signs or mortalities in fish,and thus were considered as safe.These 14γ-hemolytic isolates were represented by the genus Bacillus(13)and Stenotrophomonas(1),which might form probiotic consortia for prospective use in carp culture.