Muhammad Waseem Mumtaz

Microbial biotechnology for decolorization of textile wastewaters

Wastewater originating from the textile industry is one of the major sources of pollution for surface and groundwater bodies in countries where textiles and other dye-products are produced. Along with dyes, textile wastewaters also contain varying amounts of metals/metalloids, salts and organic pollutants. Moreover, these wastewaters have high temperatures and varying pH. Various physico-chemical and biological strategies have been devised to remove dye contaminants from such wastewaters. However, biotechnological approaches have attracted worldwide attention for their relative cost-effectiveness and environmentally friendly nature. Most biotechnological approaches rely on the use of microbes that have the potential to enzymatically degrade and decolorize dye-containing textile effluents. During recent years, several microbial cultures as well as microbial enzymes have been characterized and used for removal of dyes from simulated wastewaters having defined chemical compositions. However, there are still many challenges in scaling up microbial and enzymatic technologies for decolorization of raw textile wastewater that contain metals/metalloids, salts and other toxic compounds. The present review article summarizes the findings of recent studies conducted on decolorization of raw textile wastewaters. To the best of our knowledge, this is the only review reporting the biodegradation of azo dyes in raw textile effluents.

Optimized biodiesel production and environmental assessment of produced biodiesel

Present study deals with the optimization of biodiesel production using rapeseed oil as feedstock and NaOCH3 as a catalyst. Optimization of different reaction parameters, such as catalyst concentration, reaction temperature, reaction time. and alcohol to oil molar ratio, was done using response surface methodology (RSM). The optimal experimental conditions for biodiesel production were as follows: catalyst concentration (%) 0.30, reaction temperature 55°C, molar ratio 6.75, and reaction time 60 min. Under these optimal conditions, 97.5 percentage yield of biodiesel was obtained. The observed and predicted values of rapeseed oil methyl esters (ROMEs) yield showed a linear relationship. The fuel properties such as specific gravity 0.876 ± 0.01, flash point 168 ± 0.48°C, fire point 197.8 ± 0.31°C, pour point −7 ± 0.060°C, cloud point −2 ± 0.10°C kinematic viscosity 4.42 ± 0.26 mm2/sec, and sulfur content 0.002 mg/Kg of the produced biodiesel show the suitability of rapeseed oil biodiesel, as fuel. Moreover, engine performance test of the Rapeseed oil biodiesel (rapeseed oil methyl esters, ROME) was examined. The results showed that CO and particulate matter (PM) emissions of the ROME were lower than those of diesel fuel. NOX emissions of the ROME were lower for B5, B20, B40, and B50, while higher for B80 and B100. These results show the environment benefits of biodiesel.

Evaluation of pollution load of Lahore Canal by quantification of various pollutants through physicochemical characterisation

The work describes the physicochemical analysis of the water samples collected from Lahore Canal to evaluate pollution load at different points of the canal. Different physical and chemical pollutants such as temperature, pH, electrical conductivity, total dissolved and suspended solids, turbidity, chlorides, sulphates, nitrates, oils and grease, dissolved oxygen, chemical oxygen demand and biological oxygen demand (BOD) were analysed. The data was analysed through analysis of variance, which showed that the p values for dissolved oxygen (DO), chemical oxygen demand (COD), BOD, electrical conductivity, total dissolved solid (TDS), total suspended solid (TSS), turbidity, oil and grease, sulphates, and nitrates are <0.05, while p value of temperature, pH, and chlorides are 1.000, 0.984, and 0.070, respectively, which are >0.05. Further regression analysis revealed that the simple line regression modal is fit for turbidity and TSS, electrical conductivity and TDS, COD and DO, BOD and DO, and BOD and COD. The studies reveal that Lahore Canal is receiving a considerable amount of physical and chemical pollutants at different points.

RSM Based Optimization of Chemical and Enzymatic Transesterification of Palm Oil: Biodiesel Production and Assessment of Exhaust Emission Levels

Current study presents RSM based optimized production of biodiesel from palm oil using chemical and enzymatic transesterification. The emission behavior of biodiesel and its blends, namely, POB-5, POB-20, POB-40, POB-50, POB-80, and POB-100 was examined using diesel engine (equipped with tube well). Optimized palm oil fatty acid methyl esters (POFAMEs) yields were depicted to be 47.6 ± 1.5, 92.7 ± 2.5, and 95.4 ± 2.0% for chemical transesterification catalyzed by NaOH, KOH, and NaOCH3, respectively, whereas for enzymatic transesterification reactions catalyzed by NOVOZYME-435 and A. n. lipase optimized biodiesel yields were 94.2 ± 3.1 and 62.8 ± 2.4%, respectively. Distinct decrease in particulate matter (PM) and carbon monoxide (CO) levels was experienced in exhaust emissions from engine operating on biodiesel blends POB-5, POB-20, POB-40, POB-50, POB-80, and POB-100 comparative to conventional petroleum diesel. Percentage change in CO and PM emissions for different biodiesel blends ranged from −2.1 to −68.7% and −6.2 to −58.4%, respectively, relative to conventional diesel, whereas an irregular trend was observed for NOx emissions. Only POB-5 and POB-20 showed notable reductions, whereas all other blends (POB-40 to POB-100) showed slight increase in NOx emission levels from 2.6 to 5.5% comparative to petroleum diesel.

Decolorization of Reactive Black-5 by Shewanella sp. in the Presence of Metal Ions and Salts.

In this study, effect of various metal ions and salts on biodecolorization of Reactive black-5, azoreductase activity, and growth of Shewanella sp. strain IFN4 was evaluated. Among the tested metals, Cr²⁺, Pb(²⁺, Ni²⁺, Fe²⁺, and Mn²⁺ did not inhibit the biodecolorization of reactive black-5, azoreductase activity and bacterial growth. Three metals (Cu²⁺, Zn²⁺, and Co²⁺) delayed the decolorization process without completely inhibiting the reaction and also suppressed the bacterial growth. However, no dye decolorization was observed in the presence of Cd²⁺ (10 mg L⁻¹). Furthermore, bacterium decolorized the dye at high concentration (15 mg L⁻¹) of mixed metal ions. Strain IFN4 was also able to decolorize the dye at 50 g NaCl L⁻¹ and 60 g Na₂SO₄ L⁻¹. NaCl was found to be more inhibitory to bacterial growth than Na₂SO₄and the reverse was observed for azoreductase activity. These findings suggest that strain IFN4 could be used in designing a bioreactor for the treatment of textile effluent.

Trichoderma harzianum: a green sorbent for Pb(II) uptake from aqueous solutions

This investigation describes the use of specially cultivated, nonliving biomass of Trichoderma harzianum as a biosorbent for the batch removal of Pb(II) from a stirred system under different experimental conditions. The metal removal depended upon pH, sorbent particle size, initial Pb(II) concentration, shaking speed, and sorption time. The optimal experimental conditions for the removal of Pb(II) by T. harzianum with an initial metal concentration of 100 mg L−1 were obtained at a particle size of 53 μm, a pH of 4.5, a shaking speed of 200 rpm, and a contact time of 720 min. The results were analyzed in terms of adsorption isotherms and kinetic models. The Freundlich isotherm model and pseudo second-order model fitted well in the data. T. harzianum proved to be a good biomaterial for accumulating Pb(II) from aqueous solutions (q = 460 mg g−1).

Biotechnology: A powerful tool for the removal of cadmium from aquatic systems

The prime objective of the present research work was to evaluate the efficiency of bio-machine for the removal of Cadmium (Cd) from aquatic systems. Aspergillus niger fungus was used as bio-machine to remove Cd from aquatic systems. Twenty three different strains (IIB-1 to IIB-23) were isolated from industrial effluents and the Langmuir and Freundlich models were applied to the best Cadmium removal strain IIB-23 in order to obtain the adsorption parameters. Different parameters such as pH, temperatur e, contact time, initial metal concentratio, and biomass dosage on the biosorption of Cd were studied. The percent removal of Cd initially increased with an increase in pH ranging from 5.5-6.5 and then decreased by increasing pH from 7.0-7.5. An optimized pH used for Cd removal from aquatic systems was found to be 6.5. Additionally, an optimum amount of biomass was 1.33 g for the maximum removal of Cd from the aqueous solutions with initial metal concentration of 75 mg/L. The results obtained thus indicated that Langmuir model is the best suited for the removal of Cd from aquatic systems.

Evaluating the potential of oleaginous yeasts as feedstock for biodiesel production

BACKGROUND Lipid-producing microorganisms, said to be oleaginous have been recognized since several years. We had investigated the effects of medium components and culturing situations on cell growth and lipid accumulation of oleaginous yeasts which were analytically examined so as to enhance lipid yield for biodiesel production. OBJECTIVE The main objective of this study was to explore oleaginous yeast, Yarrowia lipolytica isolated from soil and optimization of culture conditions and medium components to obtained better quality microbial oil for biodiesel production. METHODS Fifty yeast strains were isolated from soil from different regions of Lahore and eleven of them were selected for oil production. The isolated yeast colonies were screened to further check their lipid producing capabilities by the qualitative analysis. Five yeast strains were designated as oleaginous because they produced more than 16% of oil based on their biomass. To estimate the total lipid content of yeast cells, the extraction of lipids was done by performing the procedure proposed by Bligh and Dyer. The transesterification of yeast oils was performed by using different methods. There were three different strategies customized to transesterifying microbial oil using base catalyzed transesterification, acid catalyzed transesterification and enzyme-based transesterification. After completion of transesterification, sample was used for fatty acid methyl esters (FAMEs) were analyzed by gas-chromatograph with ionization detector type MS. RESULTS The isolate IIB-10 identified as Yarrowia lipolytica produced maximum amount of lipids i.e. 22.8%. More amount of biomass was obtained when cane molasses was utilized as carbon source where it produced 29.4 g/L of biomass while sucrose and lactose were not utilized by IIB-10 and no biomass was obtained. Similarly, meat extracts showed best results when it was used as nitrogen source because it resulted in 35.8 g/L biomass of Yarrowia lipolytica IIB-10. The culturing conditions like size of inoculum, effect of pH and time of incubation were also studied. The 10% of inoculum size produced 25.4 g/L biomass at 120 h incubation time, while the pH 7 was the optimum pH at which 24.8 g/L biomass was produced by Yarrowia lipolytica IIB-10. GC-MS analysis showed that biodiesel produced by transesterification contained similar fatty acids as found in vegetable oil for this reason it is widely accepted feedstock for biodiesel production. CONCLUSION The analysis of fatty acids methyl esters showed the similar composition of microbial oil as in vegetable oils and high amount of methyl esters were obtained after transesterification. Therefore, potentially oleaginous yeast could be used to generate a large amount of lipids for biodiesel production that will be the better substitute of petroleum-based diesel and will also control the environmental pollution.