Optimization of alkaline protease production from Shewanella oneidensis MR‐1 by response surface methodology

BACKGROUND: The proteases are among the most important groups of enzymes. Therefore, it is important to produce inexpensive and optimized media for large‐scale commercial production. In the present work, three different Shewanella species were screened on skim milk agar medium for their ability to produce alkaline protease. The effects of different culture conditions were optimized for alkaline protease production by S. oneidensis MR‐1 using a Box–Behnken design combined with response surface methodology (RSM). RESULTS: Highest yield (112.90 U mL^?1) of protease production was obtained at pH 9.0, a temperature of 30 °C, glucose (12.5 g L^?1), tryptone (12.5 g L^?1) and an incubation period of 36 h. A second‐order polynomial regression model was used for analysis of the experiment. The experimental values were in good agreement with predicted values, with correlation coefficient 0.9996. CONCLUSION: Carbon and nitrogen, pH, temperature and incubation period were chosen as the main factors to be used in an experimental design for optimization to produce low‐cost enzymes, potentially for use on an industrial scale. A 60% increase in enzyme activity was achieved in the optimized medium compared with the original medium. Copyright © 2008 Society of Chemical Industry     

Review of the process development aspects of electrochemical dyeing: its impact and commercial applications

This review discusses the recent progress made in both direct and indirect electrochemical dyeing processes and the parameters that control the dyeing process.     

Influence of inhibitors on corrosion and anodic behaviour of different grades of aluminium in alkaline media

The electrochemical properties of different grades of aluminium are said to be dependent on the presence of minor amounts of iron and silicon impurities. This investigation aims mainly at addressing the influence of different inhibitors (e.g., sodium stannate, sodium citrate and calcium oxide combinations) on properties such as corrosion, anodic behaviour and anode utilization efficiency of different grades of aluminium in alkaline media.     

Sunflower Acid Oil-Based Production of Rhamnolipid Using Pseudomonas aeruginosa and Its Application in Liquid Detergents

Utilization of industrial waste as substrates for the rhamnolipid synthesis by Pseudomonas aeruginosa is a worthy alternative for conventionally used vegetable oils and fatty acids to reduce the production cost of rhamnolipid. Sunflower acid oil (SAO), a by-product of the oil industry, contains 70% 18:0 fatty acid, with oleic acid as a major component. In this scope, production and analysis of rhamnolipid was successfully demonstrated using SAO as a new substrate. Pseudomonas aeruginosa produced rhamnolipid (a glycolipid biosurfactant) at a maximum concentration of 4.9 g L⁻¹ with 60 g L⁻¹ of SAO in the medium. Structural properties of rhamnolipid biosurfactant are confirmed using thin layer chromatography (TLC), high performance liquid chromatography (HPLC), and fourier transformed infrared spectroscopy (FTIR) analysis. Further surface-active properties of the crude rhamnolipid were evaluated by measuring surface tension and emulsification properties. The synthesized rhamnolipid reduced the surface tension of water to 30.12 mN m⁻¹ and interfacial tension (against heptane) to 0.52 mN m⁻¹. Moreover, rhamnolipid shows the highest emulsification index (above 80%) for vegetable oils. This study confirms the use of SAO as a potential substrate for rhamnolipid production. The synthesized rhamnolipid was incorporated in liquid detergent formulation along with alpha olefin sulfonate (AOS) and sodium lauryl ether sulfate (SLES). The performance properties including foaming and cleaning efficiency of liquid detergent were compared.     

Cloud Security Service for Identifying Unauthorized User Behaviour

Recently, an innovative trend like cloud computing has progressed quickly in Information Technology. For a background of distributed networks, the extensive sprawl of internet resources on the Web and the increasing number of service providers helped cloud computing technologies grow into a substantial scaled Information Technology service model. The cloud computing environment extracts the execution details of services and systems from end-users and developers. Additionally, through the system’s virtualization accomplished using resource pooling, cloud computing resources become more accessible. The attempt to design and develop a solution that assures reliable and protected authentication and authorization service in such cloud environments is described in this paper. With the help of multi-agents, we attempt to represent Open-Identity (ID) design to find a solution that would offer trustworthy and secured authentication and authorization services to software services based on the cloud. This research aims to determine how authentication and authorization services were provided in an agreeable and preventive manner. Based on attack-oriented threat model security, the evaluation works. By considering security for both authentication and authorization systems, possible security threats are analyzed by the proposed security systems.     

Data reduction methodologies for single fibre fragmentation test: Role of the interface and interphase

The single fibre fragmentation test (SFFT) is commonly used to characterise the fibre/matrix adhesion. In order to quantify the fibre/matrix adhesion the cumulative stress transfer function (CSTF) methodology was developed so that the elastoplasticity of the matrix could be included in the analysis through the plasticity-effect model [Tripathi D, Chen F, Jones FR. A comprehensive model to predict the stress fields in a single fibre composite. J Comp Mater 1996;30;1514–38., Tripathi D, Jones FR. Measurement of the load-bearing capability of the fibre/matrix interface by single fibre fragmentation. Comp Sci Technol 1997;57:925–35.] The limitations of this technique for the data reduction have been addressed by the use of the Plasticity Model to input the non-linearity of the matrix into methodology for fragmentation of a fibre in a matrix. An improved methodology, known as the revised cumulative stress transfer function (RCSTF) is described. The adhesion of a nanoscale plasma copolymer coated glass/epoxy system has been used to examine this approach to the fragmentation process. This methodology is also extended to account for the presence of an interphase. To validate the three phase model, carbon fibre coated with high and medium modulus epoxy resin were used to simulate fibre/interphase/matrix.     

Inhibiting and accelerating effects of aminophenols on the corrosion and permeation of hydrogen through mild steel in acidic solutions

The influence of aminophenols on the corrosion and hydrogen permeation of mild steel in 1 M HCl and 0.5 M H₂SO₄ has been studied using weight loss and gasometric measurements and various electrochemical techniques. All the isomers of aminophenol inhibit the corrosion of mild steel in 1 M HC1 and accelerate it in 0.5 M H₂SO₄. They behave predominantly as cathodic inhibitors. Aminophenols, except PAP in I M HCI, enhance the permeation current in both the acids. The adsorption of PAP on the mild steel surface in 1 M HCl obeys the Langmuir adsorption isotherm. Surface analysis and ultraviolet spectral studies are also carried out to establish the mechanism of corrosion inhibition and acceleration of mild steel in acidic solutions.     

Characterization of reduced graphene oxide obtained from vacuum-assisted low-temperature exfoliated graphite

Microsystem Technologies - Graphene consists of sheets of two-dimensional allotrope carbons and is a basic element of graphite. Herein, reduced graphene oxide (rGO) were exfoliated from graphite...     

Imprecise probabilistic query answering using measures of ignorance and degree of satisfaction

In conditional probabilistic logic programming, given a query, the two most common forms for answering the query are either a probability interval or a precise probability obtained by using the maximum entropy principle. The former can be noninformative (e.g., interval [0, 1]) and the reliability of the latter is questionable when the priori knowledge is imprecise. To address this problem, in this paper, we propose some methods to quantitatively measure if a probability interval or a single probability is sufficient for answering a query. We first propose an approach to measuring the ignorance of a probabilistic logic program with respect to a query. The measure of ignorance (w.r.t. a query) reflects how reliable a precise probability?for the query can be and a high value of ignorance suggests that a single probability is not suitable for the query. We then propose a method to measure the probability that the exact probability of a query falls in a given interval, e.g., a second order probability. We call it the degree of satisfaction. If the degree of satisfaction is high enough w.r.t. the query, then the given interval can be accepted as the answer to the query. We also prove our measures satisfy many properties and we use a case study to demonstrate the significance of the measures.