Optimization of extracellular catalase production from Aspergillus phoenicis K30 by a linear regression method using date flour as single carbon source and purification of the enzyme

Aspergillus phoenicis K30 is the selected mutant which produces an amount of extracellular catalase. To amplify the extracellular catalase production by the strain, a fermentation optimization was performed. To select the factors affecting the production, nine active variables (factors) consisting of 12 experiments were analyzed by Plackett-Burman design. Each variable was tested at two levels, a higher and a lower level. The studies of the effect of each variable and the establishment of a correlation between the response of enzyme activity and variables revealed that the link is a multiple linear regression form. The optimization was carried out through a simplex algorithm. The amount of extracellular catalase produced by the strain in the optimized medium was about four times higher than that obtained in non optimized medium corresponding to 3820 mg/L of extracellular proteins including 59500 U/L of extracellular catalase activity after 96 h of fermentation. The steps of purification were allowed to improve enzyme activity by 305-fold. From an analytical gel electrophoresis under native conditions, an apparent molecular mass of 158 kDa was determined suggesting that the enzyme is a homodimer. The isoelectric point of the protein was found to be 5 ± 0.1 as determined by a Pharmacia Phast-system.Keywords: Aspergillus phoenicis, extracellular catalase purification, dates flour, optimization, multiple linear regression.African Journal of Biotechnology Vol. 12(19), pp. 2646-265

Upper mantle anisotropy beneath the Geoscope stations

International audienceSeismic anisotropy has been widely studied this last decade, particularly by measuring splitting of vertically propagating core shear waves. The main interest in this technique is to characterize upper mantle flow beneath seismic stations. On the other hand, the major restriction in this method is that a single station gives a single anisotropy measurement. Alternative methods have been developed in order to avoid this restriction. An accurate determination of upper mantle seismic anisotropy beneath a seismic station may allow one, by doing anisotropy correction, to characterize remote or deeper anisotropy. The Geoscope network is ideal for this purpose because it is composed of a large set (about 26) of high-quality, broadband seismometers globally distributed and because some of these stations have run for more than 10 years and most of them for more than 5 years. We selected about 100 events at each site, generally of magnitude (m b) > 6.0, and we performed systematic measurements of the splitting parameters (fast polarization direction φ and delay time δt) on SKS, SKKS, and PKS phases. Splitting on oceanic islands has been difficult to observe owing to the low quality of the signal but also perhaps owing to complex upper mantle structures beneath the stations. Station KIP (Kipapa, Hawaii) in the Pacific is the only oceanic Geoscope station with a clear anisotropy. We determined well-constrained splitting parameters for 10 of the 17 continental stations that may be explained by a single anisotropic layer. The poor correlation between fast polarization directions and the absolute plate motion together with the apparent incoherence between the plate velocities and the observed delay times suggest that a simple drag-induced asthenospheric flow alone fails to explain most of the observations. For some stations located on or near major lithospheric structures (TAM, Tamanrasset, Algeria, for instance), we observe a good correlation between fast polarization directions and regional structures. At station SCZ (Santa Cruz, California), we found clear variations of the splitting parameters as a function of the event backazimuth, compatible with two layers of anisotropy. Three stations (CAN (Canberra), HYB (Hyderabad, India) and SSB (Saint Sauveur Badole, France)) seem to be devoid of detectable anisotropy

Lithologie, evolution structurale et geodynamique des terrains precambriens d'Abankor-Timgaouine (Hoggar occidental, Algerie)

SIGLET 55648 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Optimization survey of gas CO2 sequestration in the TAGS Algerian reservoirs

This work is devoted to present the experience of Gas CO2 Storage in Algeria. The study was done to optimise the best reservoir for Gas CO2 Storage. The risks name for the two Fields considered Field I & Field II, they are: Permeable Zone in Seal, Earthquake Induced Fracturing, Leakage - Undetected Fault, NW Fractures corridors (that linear features are connected fracture corridors and, with current injection plan, could propagate through seal allowing CO2 into potable aquifer), Injection Well Leakage (With increasing pressure an inadequate barrier in wellbore material provides a leakage path to potable aquifer or surface), Old Well Leakage (Inadequate completion or chemical alteration of wellbore material provides a leakage path to potable aquifer or surface), Exceeding Spill-Point (Restricted access to pore space within structure causes CO2 flow below spill point, leaking up-dip to unknown resource potential) and Migration Direction

Effects of footwear midsole hardness on females' lower limb kinetics and kinematics during cutting manoeuvres

International audienc

Moho depth derived from gravity and magnetic data in the Southern Atlas Flexure (Algeria)

International audienceExisting aeromagnetic and gravity data were used to study the structure of the Southern Atlas Flexure (SAF) in Algeria. Forward and inverse numerical modelings were applied, giving access to the depth of the Moho and the Curie depth in this area. Our results suggest a maximum crustal thickness of about 48 km, and a Curie depth of about 20 km. We then discuss the implications of those results on the regional structure of the SAF, also using cross-sections built using 2D-geological modeling. (C) 2016 Elsevier Ltd. All rights reserved

Active Coastal Thrusting and Folding, and Uplift Rate of the Sahel Anticline and Zemmouri Earthquake area (Tell Atlas, Algeria)

International audienceMajor uplifts of late Quaternary marine terraces are visible along the coastline of the Tell Atlas of Algeria located along the Africa-Eurasia convergent plate boundary. The active tectonics of this region is associated with large shallow earthquakes (M≥6.5), numerous thrust mechanisms and surface fault-related fold. We conducted a detailed levelling survey of late Pleistocene and Holocene marine notches in the Algiers region that experienced 0.50 m coastal uplift during the 2003 Zemmouri earthquake (Mw 6.8). East of Algiers, Holocene marine indicators show three pre-2003 main notch levels formed in the last 21.9 ka. West of Algiers on the Sahel anticline, the levelling of uplifted marine terraces shows a distinct staircase morphology with successive notches that document the incremental folding uplift during the late Pleistocene and Holocene. The timing of successive uplifts related to past coseismic movements along this coastal region indicates episodic activity during the late Holocene. Modelling of surface deformation in the Zemmouri earthquake area implies a 50-km-long, 20-km-wide, NE-SW trending, SE dipping fault rupture and an average 1.3 mcoseismic slip at depth. Further west, the 70-km-long Sahel fold is subdivided in 3 sub-segments and shows ~0.84- 1.2 mm/yr uplift rate in the last 120-140 ka. The homogeneous Holocene uplift of marine terraces and the anticline dimensions imply the possible occurrence of large earthquakes with Mw≥7 in the past. The surface deformation and related successive uplifts are modelled to infer the size and characteristics of probable future earthquakes and their seismic hazard implications for the Algiers region

H/V ambient noise for a rapid assessement of an unstable zone geometry : road slide case in Lakhdaria (Algeria)

Following torrential rainfall that struck the area of Lakhdaria during the winter of 2006, a slide road slope carried away half of the road on forty meters length, leaving a five meters high scarp. The remaining part of the road and houses located upstream were threatened by a potential second slip as showed by the cracks and the déformations observed around the scarp. Ambient vibration recordings were carried out 3 days after this event, with the aim of circumscribing the unstable zone around the scarp, characterized by a strongly disturbed soil. The results of this study showed that in the investigated area, H/V curves exhibit a frequency peak around 6 Hz behind the edge of the scarp and another one around 2 Hz, along the road, on both sides of the scarp. The first peak is related to the disturbed and unstable section of the soil, which is about 6m thick (slip surface depth), in good agreement with field observations and confirmed by geotechnical investigations. The second peak is related to a deeper geological interface. Upstream of the road, where there are some houses, H/V curves are flat, indicating the absence of the strongly disturbed soil section. These results allowed us to rapidly evaluate the lateral extension and thickness of the unstable zone. This study shows the reliability of H/V ambient vibration method to characterize the geometry of "fresh" sliding zones or unstable disturbed soil masses