Ali Hussain

Exploited application of sulfate-reducing bacteria for concomitant treatment of metallic and non-metallic wastes: a mini review

A variety of multidimensional anthropogenic activities, especially of industrial level, are contaminating our aquatic and terrestrial environments with a variety of metallic and non-metallic pollutants. The metallic and non-metallic pollutants addressed specifically in this review are heavy metals and various compound forms of sulfates, respectively. Direct and indirect deleterious effects of the both types of pollutants to all forms of life are well-known. The treatment of such pollutants is therefore much necessary before their final discharge into the environment. This review summarizes the productive utility of sulfate-reducing bacteria (SRB) for economical and concomitant treatment of the above mentioned wastes. Utilization of agro-industrial wastes and some environmental contaminants including hydrocarbons, as economical growth substrates for SRB, is also suggested and proved efficient in this review. Mechanistically, SRB will utilize sulfates as their terminal electron acceptors during respiration while utilizing agro-industrial and/or hydrocarbon wastes as electron donors/carbon sources and generate H2S. The biogenic H2S will then react vigorously with dissolved metals present in the wastewaters thus forming metal sulfide. The metal sulfide being water insoluble and heavier than water will settle down in the water as precipitates. In this way, three types of pollutants i.e., metals, sulfates and agro-industrial and/or hydrocarbon wastes will be treated simultaneously.

Microbial production and industrial applications of keratinases: an overview

Massive production of keratinaceous byproducts in the form of agricultural and industrial wastes throughout the world necessitates its justified utilization. Chemical treatment of keratin waste is proclaimed as an eco-destructive approach by various researchers since it generates secondary pollutants. Microbial degradation of keratin waste is an emerging and eco-friendly approach and offers dual benefits, i.e., treatment of recalcitrant pollutant (keratin) and procurement of a commercially important enzyme (keratinase). This review summarizes the potential utility of some bacterial and fungal species for the production of keratinase using a variety of keratinaceous wastes as growth substrates. The application of microbial keratinases in waste management; animal feed, detergent, and fertilizer manufacturing; and leather, cosmetic, and pharmaceutical industries is also abridged in this review.

Biphasic Treatment System for the Removal of Toxic and Hazardous Pollutants from Industrial Wastewaters

Industrial effluents carrying diverse pollutants are discharged freely into the adjacent environments and percolate to the groundwater resources. Currently, the treatment strategies also consider recycling and reuse with the energy recovery. Novel approaches to remove these pollutants include biphasic systems. Different biphasic systems including liquid-liquid two-phase partitioning and solid-liquid partitioning systems have proved successful for the cleaning of effluents containing textile dyes, heavy metals, organic contaminants, pharmaceutical ingredients and many other xenobiotic compounds. The system efficacy is based on the careful selection of the phase-forming substance/polymer as well as control and maintenance of the operational parameters including temperature, pH and hydraulic retention time. Among the biological parameters, selection of the microbes either pure cultures or mixed cultures plays a very important role for the removal of xenobiotics in biphasic systems.

Diversity and conservation of freshwater turtles in Pakistan: a review

Abstract Broadly speaking, turtles are represented by five families, 13 genera and 15 species in Pakistan, with freshwater turtles belonging to two families, six genera and eight species. Hardshell species include b lack pond turtle (Geoclemys hamiltonii), c rowned river turtle (Hardella thurjii), b rown roofed turtle (Pangshura smithii) and Indian roofed turtle (Pangshura tectum), while softshell species include Indian narrow-headed softshell turtle (Chitra indica), Ganges softshell turtle (Nilssonia gangeticus), Indian peacock softshell turtle (Nilssonia hurum) and Indian flapshell turtle (Lissemys punctata andersonii). Major threats to turtle populations in Pakistan include weak law enforcement, illegal trade, lack of awareness about the ecological role of the taxa, fishing activities and environmental pollution. As a result, three species are particularly vulnerable, namely Geoclemys hamiltonii, Hardella thurjii and Aspideretes gangeticus whereas Chitra indica is endangered and Kachuga smithii is near threatened. For successful conservation of turtles in Pakistan, it is essential that databases on diversity, distribution and the current status of various species in the country are developed and updated. In addition, conservation campaigns must be launched to raise awareness within local communities and school children regarding the important role turtles play within ecosystems. Establishing rescue and information centres at specific sites is also an absolute must for the protection of these environmentally friendly creatures.