Simultaneous biodegradation of phenol and cyanide present in coke-oven effluent using immobilized Pseudomonas putida and Pseudomonas stutzeri

ABSTRACT Discharge of coke-oven wastewater to the environment may cause severe contamination to it and also threaten the flora and fauna, including human beings. Hence before dumping it is necessary to treat this dangerous effluent in order to minimize the damage to the environment. Conventional technologies have inherent drawbacks however, biological treatment is an advantageous alternative method. In the present study, bacteria were isolated from the soil collected from the sites contaminated by coke-oven effluent rich in phenol and cyanide. Nucleotides sequence alignment and phylogenetic analysis showed the identity of the selected phenol and cyanide degrading isolates NAUN-16 and NAUN-1B as Pseudomonas putida and Pseudomonas stutzeri, respectively. These two isolates tolerated phenol up to 1800 mg L-1 and cyanide up to 340 mg L-1 concentrations. The isolates were immobilized on activated charcoal, saw dust and fly ash. The effluent was passed through the column packed with immobilized cells with a flow rate of 5 mL min-1. The isolates showed degradation of phenol up to 80.5% and cyanide up to 80.6% and also had the ability to reduce biological oxygen demand, chemical oxygen demand and lower the pH of effluent from alkaline to near neutral. The study suggests the utilization of such potential bacterial strains in treating industrial effluent containing phenol and cyanide, before being thrown in any ecosystem.

Transverse Discrepancy in Orthodontics: A Review.

In today’s orthodontic practice esthetics is a primary concern both for patient and the orthodontist. The perception of esthetics for a lay person largely depends on the symmetry of the face. Hence, diagnosis and correction of the transverse discrepancy are imperative for optimum result. Some occlusal relations can result from skeletal jaw relation or from tooth positions. Malocclusion can occur in three planes of space, i.e., sagittal, transverse, and vertical plane. Transverse discrepancy is “An abnormality of development in transverse plane.” In orthodontic diagnosis and treatment planning, the emphasis is placed on recognizing asymmetry and achieving symmetric results with dental midlines coincident with each other and with the facial midline. Humans, like most other animals, are considered to display bilateral symmetry. By strict definition, this implies that mirror-image mathematical identity exists between right and left halves. In orthodontic diagnosis and treatment planning, emphasis is placed on recognizing asymmetry and achieving symmetric results. Treatment of an asymmetry can be challenging. The 1st treatment step is to diagnose if the asymmetry is of functional, dental or skeletal cause. The treatment options for transverse problem may include arch coordination, asymmetric extraction, asymmetric mechanics, and skeletal correction by orthopedic or surgical procedure. However, it is crucial to determine that the observed asymmetry is genuine and not the product of a functional or habitual shift of the mandible as is often the case with unilateral cross-bites due to reduced width of the maxillary arch.