A halophilic bacterial consortium was enriched from Red Sea saline water and sediment samples collected from Abhor, Jeddah, Saudi Arabia. The consortium potentially degraded different low (above 90% for phenanthrene and fluorene) and high (69 ± 1.4 and 56 ± 1.8% at 50 and 100 mg/L of pyrene) molecular weight polycyclic aromatic hydrocarbons (PAHs) at different concentrations under saline condition (40 g/L NaCl concentration). The cell hydrophobicity (91° ± 1°) and biosurfactant production (30 mN/m) confirmed potential bacterial cell interaction with PAHs to facilitate biodegradation process. Co-metabolic study with phenanthrene as co-substrate during pyrene degradation recorded 90% degradation in 12 days. The consortium in continuous stirred tank reactor with petroleum refinery wastewater showed complete and 90% degradation of low and high molecular weight PAHs, respectively. The reactor study also revealed 94 ± 1.8% chemical oxygen demand removal by the halophilic consortium under saline condition (40 g/L NaCl concentration). The halophilic bacterial strains present in the consortium were identified as strain CEES1 (KX377976), strain CEES2 (KX377977), strain CEES3 (KX377978) and strain CEES4 (KX377979). Thus, the promising halophilic consortium was highly recommended to be employed in petroleum saline wastewater treatment process.

Single chamber air cathode microbial fuel cell (MFC) is a promising and sustainable technology to generate electricity. In the present study, the potential of air cathode MFC treating dye processing wastewater was investigated at various organic loads with interest focused on power densities, organic removal and coulombic efficiencies. The highest power density of about 515 mW/m 2 (6.03 W/m 3) with 56% of coulombic efficiency was procured at 1.0 (g COD/L) organic load. The high potency of TCOD (total chemical oxygen demand), SCOD (soluble chemical oxygen demand) and TSS (Total Suspended Solids) removal of about 85%, 73% and 68% respectively was achieved at the organic load of 1.0 (g COD/L). The bacterial strains in anode region at the initial stage of MFC operation were reported to be responsible for potential organic removal. The bacterial strains in air cathode MFC were identified as Paenibacillus sp. strain JRA1 (MH27077), Pseudomonas sp. strain JRA2 (MH27078), Ochrobactrum sp. strain JRA3 (MH27079), Sphingobacterium sp. strain JRA4 (MH27080), Stenotrophomonas sp. strain JRA5 (MH27081), Bacillus sp. strain JRA6 (MH27082) and Clostridium sp. strain JRA7 (MH27083) using phylogenetic analysis. After 60 days of air cathode MFC operation, the bacterial community in biofilm samples was dominated by Bacillus, Ochrobactrum and Pseudomonas (20-22%). The biofilm sample collected from the carbon brush consisted of Bacillus (33%), Ochrobactrum (30%), Pseudomonas (28%), Clostridium (6%) and Stenotrophomonas (3%). The present study revealed the treatment efficiency of dye processing wastewater along with power generation in single chambered air cathode MFC.

Of 131 bacterial isolates from seaweed, a culture of Bacillus licheniformis produced a novel protein with antibacterial activity against methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci, and Listeria monocytogenes. The antibacterial activity was maximal in cultures prepared in Columbia broth containing pieces of synthetic polyurethane sponge and shaken at 210 to 230 rpm. Antibacterial activity was not found in cultures grown statically or with different speeds of rotary shaking. Reduced activity was apparent in supernatants prepared from marine 2216E broth and tryptone soya broth with or without 1% (wt/vol) sodium chloride. The antibacterial compound was sensitive to proteinase K, pronase, and trypsin, but was not affected by Tween-20, -40, -60, or -80, or alpha- or beta-amylase. Activity was not adversely affected by heating up to 40 degrees C or treatment at pH 5 to 14. The bioactive compound was determined to be associated with a protein of 30.7 kDa, which had homology to the YbdN protein of B. licheniformis ATCC 14580.

With the significant increases in the human population, global aquaculture has undergone a great increase during the last decade. The management of optimum conditions for fish production, which are entirely based on the physicochemical and biological qualities of water, plays a vital role in the prompt aquaculture growth. Therefore, focusing on research that highlights the understanding of water quality and breeding systems’ stability is very important. The biofloc technology (BFT) is a system that maximizes aquaculture productivity by using microbial biotechnology to increase the efficacy and utilization of fish feeds, where toxic materials such as nitrogen components are treated and converted to a useful product, like a protein for using as supplementary feeds to the fish and crustaceans. Thus, biofloc is an excellent technology used to develop the aquaculture system under limited or zero water exchange with high fish stocking density, strong aeration, and biota. This review is highlighted on biofloc composition and mechanism of system work, especially the optimization of water quality and treatment of ammonium wastes. In addition, the advantages and disadvantages of the BFT system have been explained. Finally, the importance of contemporary research on biofloc systems as a figure of microbial biotechnology has been emphasized with arguments for developing this system for better production of aquaculture with limited natural resources of water.

Finfish aquaculture is one of the quickly developing food industries in the world. But, the major drawbacks of this industry are the frequent outbreak of infectious diseases due to elevated stress in an intensive culture system. Antibiotics are extensively used to combat these diseases. Prophylactic administrations of antibiotics in aquaculture lead to the emergence and spread of antibiotic-resistant pathogens which indirectly cause a risk to health of human. Therefore, hard rules and regulations have been established in various countries to minimize or ban the application of antibiotics in finfish aquaculture. Recently probiotics have garnered significant attraction as an alternative measure for disease prevention in aquaculture. Probiotics increase health status, disease resistance, growth performance and feed utilization through improving hosts microbial balance. This review presents the summary and discussion of the results of the effects of probiotic administration in the culture of commercially important finfish. Besides, the current study attempts to explore the gap in present scientific information as well as suggests concerns that worth further research.