Comparison of two-dimensional synthesized mammograms versus original digital mammograms: a quantitative assessment.

This study objectively evaluates the similarity between standard full-field digital mammograms and two-dimensional synthesized digital mammograms (2DSM) in a cohort of women undergoing mammography. Under an institutional review board-approved data collection protocol, we retrospectively analyzed 407 women with digital breast tomosynthesis (DBT) and full-field digital mammography (FFDM) examinations performed from September 1, 2014, through February 29, 2016. Both FFDM and 2DSM images were used for the analysis, and 3216 available craniocaudal (CC) and mediolateral oblique (MLO) view mammograms altogether were included in the dataset. We analyzed the mammograms using a fully automated algorithm that computes 152 structural similarity, texture, and mammographic density-based features. We trained and developed two different global mammographic image feature analysis-based breast cancer detection schemes for 2DSM and FFDM images, respectively. The highest structural similarity features were obtained on the coarse Weber Local Descriptor differential excitation texture feature component computed on the CC view images (0.8770) and MLO view images (0.8889). Although the coarse structures are similar, the global mammographic image feature-based cancer detection scheme trained on 2DSM images outperformed the corresponding scheme trained on FFDM images, with area under a receiver operating characteristic curve (AUC) = 0.878 ± 0.034 and 0.756 ± 0.052, respectively. Consequently, further investigation is required to examine whether DBT can replace FFDM as a standalone technique, especially for the development of automated objective-based methods.

Development of a novel ultrasound-assisted alkali pretreatment strategy for the production of bioethanol and xylanases from chili post harvest residue.

A novel ultrasound-assisted alkali pretreatment strategy was developed which could effectively remove lignin and hemicelluloses and improve the sugar yield from chili post harvest residue. Operational parameters that affect the pretreatment efficiency were studied and optimized. Inhibitor analysis of the hydrolyzate revealed that major fermentation inhibitors like furfural, 5-hydroxymethyl furfural as well as organic acids like citric acid, succinic acid and propionic acid were absent. Hence fermentation can be carried out without detoxification of the hydrolyzate. Changes in structural properties of the biomass were studied in relation to the pretreatment process using Scanning Electron Microscopy (SEM) and the changes in chemical composition were also monitored. The biomass pretreated with the optimized novel method could yield 0.428g/g of reducing sugars upon enzymatic hydrolysis. The hydrolyzate obtained by this novel pretreatment strategy was found to be suitable for bioethanol and xylanase production.

Production of a cellulase-free alkaline xylanase from Bacillus pumilus MTCC 5015 by submerged fermentation and its application in biobleaching.

Here, we described the production of a cellulase-free alkaline xylanase from Bacillus pumilus MTCC 5015 by submerged fermentation and its application in biobleaching. Various process parameters affecting xylanase production by B. pumilus were optimized by adopting a Plackett-Burman design (PBD) as well as Response surface methodology (RSM). These statistical methods aid in improving the enzyme yield by analysing the individual crucial components of the medium. Maximum production was obtained with 4% yeast extract, 0.08% magnesium sulphate, 30 h of inoculum age, incubation temperature of 33.5 degrees C and pH 9.0. Under optimized conditions, the xylanase activity was 372 IU/ml. Media engineering improved a 5-fold increase in the enzyme production. Scanning electron microscopy (SEM) showed significant changes on the surface of xylanase treated pulps as a result of xylan hydrolysis. Increased roughness of paper carton fibres was apparent in scanning electron micrograph due to opening of the micro fibrils present on the surface by xylanase action. The untreated pulp did not show any such change. These results demonstrated that the B. pumilus MTCC 5015 xylanase was effective in bio-bleaching of paper carton.

An alkali-thermostable xylanase from Bacillus pumilus functionally expressed in Kluyveromyces lactis and evaluation of its deinking efficiency.

This work aimed at studying the recombinant expression of an alkali- and thermo-stable xylanase from Bacillus pumilus in Kluyveromyces lactis and its use in deinking of civic paper waste. Efficient expression with a 3-fold increase in the activity than the native organism was achieved. An inducer concentration of 2.5% and medium pH of 9.0 was the best for enzyme expression. Purified enzyme showed an optimum activity at temperatures 50 and 60°C and pH 9.0 and 10.0, respectively. At pH 12.0, enzyme retained 74% and 26% activity after 2 and 3h of incubation, respectively. After incubation at 50 and 60°C for 1h, the enzyme showed 100% retention of activity, and remained active for 4h at 60°C retaining 23% residual activity. Partially purified recombinant enzyme showed higher deinking efficiency (273%) of laser print waste paper than crude xylanase from Bacillus and commercial acidic enzyme. This xylanase with superior stability characteristics could be a suitable candidate in paper and pulp industries.

Xylanase and cellulase systems of Clostridium sp.: an insight on molecular approaches for strain improvement.

Bioethanol and biobutanol hold great promise as alternative biofuels, especially for transport sector, because they can be produced from lignocellulosic agro-industrial residues. From techno-economic point of view, the bioprocess for biofuels production should involve minimal processing steps. Consolidated bioprocessing (CBP), which combines various processing steps such as pretreatment, hydrolysis and fermentation in a single bioreactor, could be of great relevance for the production of bioethanol and biobutanol or solvents (acetone, butanol, ethanol), employing clostridia. For CBP, Clostridium holds best promise because it possesses multi-enzyme system involving cellulosome and xylanosome, which comprise several enzymes such as cellulases and xylanases. The aim of this article was to review the recent developments on enzyme systems of clostridia, especially xylanase and cellulase with an effort to analyse the information available on molecular approaches for the improvement of strains with ultimate aim to improve the efficiencies of hydrolysis and fermentation.

Production, purification, characterization and over-expression of xylanases from actinomycetes.

Xylanases are a group of depolymerizing enzymes often used for the hydrolysis of xylan (present in hemicellulose) to monomeric sugars and comprise endo-xylanases (EC 3.2.1.8) and beta-xylosidases (EC 3.2.1.37). They often act in synergy with other enzymes for complete hydrolysis of hemicellulose. Xylanases find several industrial applications, for example in food and feed industries, paper and pulp industries and more recently have acquired a great role in biomass to biofuels program. Bacteria and fungi can best produce xylanases. Recent developments in rDNA technology have resulted in molecular cloning and expression of xylanases in heterologous and homologous hosts. In view of significance of the actinomycetes for the production of biotechnological products, attempts have been made in recent years to explore them for the production of industrial enzymes, including xylanses, aiming to find the enzyme with novel features. This review provides the state-of-art information and developments on the xylanases from actinomycetes, presenting the production, purification, characterization and over-expression from various actinomycetes cultures.