Fahim Ashraf Qureshi

Biodiesel From Waste Cooking Oil: Optimization of Production and Monitoring of Exhaust Emission Levels From its Combustion in a Diesel Engine

Present study describes optimized production of waste cooking oil biodiesel (WCOB) using chemical and enzymatic transesterification. Maximum WCOB yield was 89% for chemical transesterification catalyzed by NaOCH3 and 95.9% for enzymatic transesterification using NOVOZYME-435. Optimized WCOB yield was procured for chemical transesterification when reactions were performed for 90 min at 45°C using 0.75% NaOCH3 and 6:1 methanol to oil molar ratio, whereas, enzymatic transesterification at 32.50°C for 60 h using 0.75% NOVOZYME-435 and 6:1 methanol : oil molar ratio. When compared the exhaust emission levels from diesel engine exhaust operated on conventional diesel fuel with the waste cooking oil biodiesel blends (WCOB), a notable reduction (%) in CO and PM levels was observed for WCOB5, WCOB20, WCOB40, WCOB50, WCOB80, and WCOB100 whereas in case of NOx emissions reduction (%) was observed only in case of WCOB5, WCOB20, and WCOB40, respectively.

Enzymatic saccharification and lactic acid production from banana pseudo-stem through optimized pretreatment at lowest catalyst concentration.

This work estimates the potential of banana pseudo-stem with high cellulosic content 42.2-63 %, for the production of fermentable sugars for lactic acid production through statistically optimized pretreatment method. To evaluate the catalyzed pretreatment efficiency of banana pseudo stem based on the enzymatic digestibility, Response Surface Methodology (RSM) was employed for the optimization of pretreatment temperature and time using lowest concentrations of H2SO4, NaOH, NaOH catalyzed Na2S and Na2SO3 that seemed to be significant variables with P<0.05. High F and R2 values and low p-value for hydrolysis yield indicated the model predictability. The optimized condition for NaOH was determined to be conc. 1 %, temperature 130 oC for 2.6 hr; Na2S; conc. 1 %, temperature 130 oC for 2.29 hr; Na2SO3; conc. 1 %, temperature 130 oC for 2.41 hr and H2SO4; conc. 1 %, temperature 129.45 oC for 2.18 hr, produced 84.91 %, 85.23 %, 81.2 % and 76.02 % hydrolysis yield, respectively. Sulphuric acid provided 33+1 gL-1 reducing sugars in pretreatment step along with 38+0.5 gL-1 during enzymatic hydrolysis. Separate hydrolysis and fermentation of resulting sugars showed that the conversion of glucans into lactic acid reached 92 % of the theoretical yield of glucose.

Optimization of Sulfide/Sulfite Pretreatment of Lignocellulosic Biomass for Lactic Acid Production

Potential of sodium sulfide and sodium sulfite, in the presence of sodium hydroxide was investigated to pretreat the corncob (CC), bagasse (BG), water hyacinth and rice husk (RH) for maximum digestibility. Response Surface Methodology was employed for the optimization of pretreatment factors such as temperature, time and concentration of Na2S and Na2SO3, which had high coefficient of determination (R 2) along with low probability value (P), indicating the reliable predictability of the model. At optimized conditions, Na2S and Na2SO3 remove up to 97% lignin, from WH and RH, along with removal of hemicellulose (up to 93%) during pretreatment providing maximum cellulose, while in BG and CC; 75.0% and 90.0% reduction in lignin and hemicellulose was observed. Saccharification efficiency of RH, WH, BG and CC after treatment with 1.0% Na2S at 130°C for 2.3–3.0 h was 79.40, 85.93, 87.70, and 88.43%, respectively. WH treated with Na2SO3 showed higher hydrolysis yield (86.34%) as compared to Na2S while other biomass substrates showed 2.0–3.0% less yield with Na2SO3. Resulting sugars were evaluated as substrate for lactic acid production, yielding 26.48, 25.36, 31.73, and 30.31 gL−1 of lactic acid with 76.0, 76.0, 86.0, and 83.0% conversion yield from CC, BG, WH, and RH hydrolyzate, respectively.

N-Ethyl-4-methyl-N-(3-methyl-phen-yl)benzene-sulfonamide.

The title compound, C16H19NO2S, crystallizes with two crystallographically independent molecules in the asymmetric unit in which the dihedral angles between the planes defined by the aromatic rings are 35.3 (2) and 42.5 (2)°. In the crystal, intermolecular C—H⋯O hydrogen bonds stabilize the packing.

N-Benzyl-4-methyl-N-(4-methyl­phen­yl)benzene­sulfonamide

In the title molecule, C21H21NO2S, the phenyl ring makes the dihedral angles of 74.13 (11) and 80.16 (11)° with the two benzene rings, which are inclined at an angle of 43.73 (10)° with respect to each other. In the crystal, molecules are linked by intermolecular C—H⋯O hydrogen bonds along the [010] direction. In addition, a weak C—H⋯π (arene) interaction is observed.

N-{4-[(2-Methoxyphenyl)sulfamoyl]phenyl}acetamide

In the title compound, C15H16N2O4S, the S atom has a distorted tetrahedral geometry [maximum deviation: O—S—O = 118.25 (7)°]. The two aromatic rings make a dihedral angle of 62.67 (10)° with each other. An intramolecular N—H⋯O hydrogen bond forms an S(6) ring motif. In the crystal, molecules form centrosymmetric dimers via pairwise N—H⋯O interactions, forming an R 2 2(8) ring motif, and these dimers are connected by N—H⋯O hydrogen bonds, generating a three-dimensional network. Furthermore, a weak C—H⋯π interaction helps to reinforce the crystal structure. The O atom in the acetamide group is disordered over two positions with major and minor occupancies of 0.52 (5) and 0.48 (5), respectively.

Isolation, Characterization and Selection of Avermectin-Producing Streptomyces avermitilis Strains From Soil Samples.

Background: Streptomyces avermitilis, belonging to Actinomycetes, is specialized for production of avermectin, used as an anthelmintic and insecticidal agent. It is mostly found in soil and its isolation is very crucial for medically important avermectin production. Objectives: In the present study, 10 bacterial isolates lacking antimicrobial activities were isolated from the soil samples collected from different areas of Lahore, Pakistan. Materials and Methods: Three distinctive localities of Lahore were opted for soil assortment to isolate S. avermitilis. About 50 isolates of Streptomyces species were attained through selective prescreening procedures. All of these isolates were studied for production of the secondary metabolite, avermectin. Different test like soluble pigment color and melanin formation were used for identification. Biochemical characterizations of those isolates closely resembling the control in morphological characteristics, soluble pigment color and melanin formation tests were performed. Results: The 10 selected isolates were identified as the avermectin-producing strain by fermentation and characterized on ISP2 medium for aerial and reverse side mycelia color, soluble pigment color and melanin formation, in comparison with S. avermitilis DSM 41445. The best avermectin-producing isolate S1-C (10.15 mg/L) showed similar result as S. avermitilis DSM 41445, when subjected for culture characteristics analysis in different media along with biochemical characterization. Conclusions: From the results, it was concluded that agricultural lands around Pakistan Council of Scientific and Industrial Research (PCSIR) Campus Lahore were rich sources of industrially important Streptomyces, especially S. avermitilis.

Production and Screening of High Yield Avermectin B1b Mutant of Streptomyces avermitilis 41445 Through Mutagenesis

Background: Secondary metabolite production from wild strains is very low for economical purpose therefore certain strain improvement strategies are required to achieve hundred times greater yield of metabolites. Most important strain improvement techniques include physical and chemical mutagenesis. Broad spectrum mutagenesis through UV irradiation is the most important and convenient physical method. Objectives: The present study was conducted for enhanced production of avermectin B1b from Streptomyces avermitilis 41445 by mutagenesis using ultraviolet (UV) radiation, ethidium bromide (EB), and ethyl methanesulfonate (EMS) as mutagens. Materials and Methods: S. avermitilis DSM 41445 maintained on yeast extract malt extract glucose medium (YMG) was used as inoculum for SM2 fermentation medium. Spores of S. avermitilis DSM 41445 were exposed to UV radiation for physical broad spectrum mutagenesis and to EMS and EB for chemical mutagenesis. For each mutagen, the lethality rate and mutation rate were calculated along with positive mutation rate. Results: Avermectin B1b-hyper-producing mutant, produced using these three different methods, was selected according to the HPLC results. The mutant obtained after 45 minutes of UV radiation to the spores of S. avermitilis 41445, was found to be the best mutant for the enhanced production of avermectin B1b component (254.14 mg/L). Other avermectin B1b-hyper-producing mutants, were obtained from EMS (1 µL/mL) and EB (30 µL/mL) treatments, and yielded 202.63 mg/L and 199.30 mg/L of B1b, respectively. Conclusions: The hereditary stability analysis of the UV mentioning 45 minutes revealed the UV exposure time for mutants and 3 represented the colony taken from the plate irradiated for 45 minutes mutant showed that the production of avermectin B1b remained constant and no reverse mutation occurred after 15 generations.

N-Ethyl-N-(4-methyl-phen-yl)benzene-sulfonamide.

The title compound, C15H17NO2S, is twisted at the S—N bond with a C—S—N—C torsion angle of 73.90 (14)°. The dihedral angle between the aromatic rings is 36.76 (11)°.

N-{4-[(3-Methyl-phen-yl)sulfamo-yl]phen-yl}acetamide.

In the title compound, C15H16N2O3S, the central C—S(=O)2N(H)—C unit is twisted, with a C—S—N—C torsion angle of −56.4 (2)°. The benzene rings form a dihedral angle of 49.65 (15)° with each other. In the crystal, molecules are linked by N—H⋯O hydrogen bonds, generating a three-dimensional network.