Determination of some significant batch culture conditions affecting acetyl-xylan esterase production by Penicillium notatum NRRL-1249

<p>Abstract</p> <p>Background</p> <p>Acetyl-xylan esterase (AXE, <it>EC 3.1.1.72</it>) hydrolyses acetate group from the linear chain of xylopyranose residues bound by β-1,4-linkage. The enzyme finds commercial applications in bio-bleaching of wood pulp, treating animal feed to increase digestibility, processing food to increase clarification and converting lignocellulosics to feedstock and fuel. In the present study, we report on the production of an extracellular AXE from <it>Penicillium notatum </it>NRRL-1249 by solid state fermentation (SSF).</p> <p>Results</p> <p>Wheat bran at a level of 10 g (with 4 cm bed height) was optimized as the basal substrate for AXE production. An increase in enzyme activity was observed when 7.5 ml of mineral salt solution (MSS) containing 0.1% KH₂PO₄, 0.05% KCl, 0.05% MgSO₄.7H₂O, 0.3% NaNO₃, 0.001% FeSO₄.2H₂O and 0.1% (v/w) Tween-80 as an initial moisture content was used. Various nitrogen sources including ammonium sulphate, urea, peptone and yeast extract were compared for enzyme production. Maximal enzyme activity of 760 U/g was accomplished which was found to be highly significant (p ≤ 0.05). A noticeable enhancement in enzyme activity was observed when the process parameters including incubation period (48 h), initial pH (5), 0.2% (w/w) urea as nitrogen source and 0.5% (v/w) Tween-80 as a stimulator were further optimized using a 2-factorial Plackett-Burman design.</p> <p>Conclusion</p> <p>From the results it is clear that an overall improvement of more than 35% in terms of net enzyme activity was achieved compared to previously reported studies. This is perhaps the first report dealing with the use of <it>P. notatum </it>for AXE production under batch culture SSF. The Plackett-Burman model terms were found highly significant (<it>HS</it>), suggesting the potential commercial utility of the culture used (df = 3, LSD = 0.126).</p

Study of the Effect of γ-Irradiation on Copper Single Crystals by Etching Technique

The effect of γ-irradiation with low energies on samples of copper single crystals with oriented surfaces of (111), (100) and (621) was studied by etching technique. The etch pits show a formation of glide bands, polygonized walls and Blisters as result to irradiation

Optimization of Fuel Consumption for Tractor-tilled Land Area During Harrowing Operation Using Full Factorial Experimental Design

This study's aim is to improve the tractor harrowing operation's fuel consumption efficiency to cut operating costs and boost agricultural output. The field trial was conducted at Rivers Institute of Agricultural Research and Training (RIART) Farm, Rivers State University, Port Harcourt. The 4,480 m2 experimental land area, which measured 160 by 38 meters, was divided into three blocks of nine plots each. For the alternative treatment choices, each plot was laid out at 50 m by 2 m, with a path dimension of 1 m between each plot and 2 m between each block and 1 m at the sides of the outer blocks. The tilled area fuel consumption and the field test parameters (harrowing depth and tractor forward speed) were measured in accordance with their respective requirements. Statistical studies of the general full factorial design (GFFD), including model fit assessment, analysis of variance (ANOVA), main and interaction effects, multiple linear regression model, and response optimizer, were carried out using MINITAB 19 software. Standard error (SE), coefficient of determination (r2), adjusted r2, and prediction r2 were also used to test the model's validity. The influence of harrowing depth, tractor forward speed, and their interactions are statistically significant on the tilled area fuel consumption during harrowing, according to the Pareto charts of standard effect. The tilled area fuel consumption data during harrowing were nearly normally distributed, as shown by the normal probability plots, which satisfies the first requirement of the model fitness analysis. A roughly normal distribution was also visible on the histogram plot. This observation also provides more evidence in favor of the typical fuel usage distribution in tractor-tilled areas. The residual vs. fitted value graphs showed that there is no discernible pattern in the data points for tilled area fuel consumption data during harrowing, supporting the constant variance condition of the residuals. A plot of the residual versus observation order reveals that the residual points are likewise entirely random. According to the statistical study, the effects of harrowing depths, tractor forward speed, and their interactions on tractor tilled area fuel consumption during harrowing operation were significant with 95 and very significant with 99% confidence (P&lt;0.05 and P&lt;0.01 levels of significance). Also, it was demonstrated for example that the multiple linear regression could accurately predict the experimental results with a standard error of very small amounts. For the amount of fuel consumed during harrowing in the tilled area, the coefficients of determination (r2), adjusted r2, and anticipated r2 were all equal to 100%. indicating that the estimated multiple linear regression model created for the tractor tilled area fuel consumptions explained 100% of the variability in the dataset. At harrowing depth of 0.09 m and tractor forward speed of 5 Km/h, optimal tractor tilled area fuel consumption during harrowing was achieved. According to this study, the required minimum fuel consumption for tractor-tilled area under operational parameters (harrowing depth and tractor forward speed) was 6.15 L/ha

Innovation platforms: experiences with their institutional embedding in agricultural research for development

Innovation Platforms (IPs) are seen as a promising vehicle to foster a paradigm shift in agricultural research for development (AR4D). By facilitating interaction, negotiation and collective action between farmers, researchers and other stakeholders, IPs can contribute to more integrated, systemic innovation that is essential for achieving agricultural development impacts. However, successful implementation of IPs requires institutional change within AR4D establishments. The objective of this paper is to reflect on the implementation and institutionalisation of IPs in present AR4D programmes. We use experiences from sub-Saharan Africa to demonstrate how the adoption and adaptation of IPs creates both opportunities and challenges that influence platform performance and impact. Niche-regime theory is used to understand challenges, and anticipate on how to deal with them. A key concern is whether IPs in AR4D challenge or reinforce existing technology-oriented agricultural innovation paradigms. For example, stakeholder representation, facilitation and institutional embedding determine to a large extent whether the IP can strengthen systemic capacity to innovate that can lead to real paradigm change, or are merely ‘old wine in new bottles’ and a continuation of ‘business as usual’. Institutional embedding of IPs and – more broadly – the transition from technology-oriented to system-oriented AR4D approaches requires structural changes in organisational mandates, incentives, procedures and funding, as well as investments in exchange of experiences, learning and capacity development

Electronic structure and magnetic state of transuranium metals under pressure

Electronic structure of bcc Np, fcc Pu, Am, and Cm pure metals under pressure has been investigated employing the LDA+U method with spin-orbit coupling (LDA+U+SO). Magnetic state of the actinide ions was analyzed in both LS and jj coupling schemes to reveal the applicability of corresponding coupling bases. It was demonstrated that whereas Pu and Am are well described within the jj coupling scheme, Np and Cm can be described appropriately neither in {m-sigma}, nor in {jmj} basis, due to intermediate coupling scheme realizing in these metals that requires some finer treatment. The LDA+U+SO results for the considered transuranium metals reveal bands broadening and gradual 5f electron delocalization under pressure.Comment: 5 pages, 5 figure

Application Of Synthesised Zeolite A From Kankara Kaolin For Solar Adsorption Refrigeration

This paper presents the synthesis, characterization and application of a synthesised Zeolite A from Nigerian clay (kankara) for application in solar adsorption refrigeration. On the basis of X-ray diffraction, TGA and DTA experiments Zeolite A was confirmed with and adsorption capacity of 0.3 kgadsorbate/0.85 kg adsorbent, regenerative temperature of below 200oC and structural stability below 800oC.The refrigeration system used in the test consists of a 0.6 by 0.45 m2 parabolic trough concentrator, 0.6 m long and 0.25 m diameter black coated absorber, an air cooled condenser and cooling box of volume(evaporator) 0.048 m3. The refrigerator was constructed and tested at the Mechanical Engineering Department Zaria, Nigeria at location 11.11’NE in the month of April, a month with one of the highest of average solar irradiation of 900W/ m2. The lowest evaporator temperature attained was 9.8°C with a C.O.P of 28.5%

3α-Dimethyl­amino-20-(N-methyl­acetamido)­pregn-5-ene

The title compond, C26H44N2O, is an steroidal alkaloid isolated from the medicinally important plant Sarcococca saligna. The mol­ecule consists of four fused rings (A–D), having chair, half-chair, chair and envelope conformations, respectively. The dimethyl­amino group is axially oriented on ring A, whereas the (N-methyl­acetamido)­ethyl group is attached equatorially on ring D. The crystal structure is stabilized only by van der Waals forces

Transitions and Probes in Turbulent Helium

Previous analysis of a Paris turbulence experiment \cite{zoc94,tab95} shows a transition at the Taylor Reynolds number \rel \approx 700. Here correlation function data is analyzed which gives further evidence for this transition. It is seen in both the power spectrum and in structure function measurements. Two possible explanations may be offered for this observed transition: that it is intrinsic to the turbulence flow in this closed box experiment or that it is an effect of a change in the flow around the anemometer. We particularly examine a pair of ``probe effects''. The first is a thermal boundary layer which does exist about the probe and does limit the probe response, particularly at high frequencies. Arguments based on simulations of the response and upon observations of dissipation suggests that this effect is only crucial beyond \rel\approx 2000. The second effect is produced by vortex shedding behind the probe. This has been seen to produce a large modification in some of the power spectra for large \rel. It might also complicate the interpretation of the experimental results. However, there seems to be a remaining range of data for \rel < 1300 uncomplicated by these effects, and which are thus suggestive of an intrinsic transition.Comment: uuencoded .ps files. submitted to PRE. 12 figures are sent upon request to jane wang ([email protected]