To search for new cold-active lipases, a metagenomic library was constructed using cold-sea sediment samples at Edison Seamount and was screened for lipolytic activities by plating on a tricaprylin medium. Subsequently, a fosmid clone was selected, and the whole sequence of 36 kb insert of the fosmid clone was determined by shotgun sequencing. The sequence analysis revealed the presence of 25 open reading frames (ORF), and ORF20 (EML1) showed similarities to lipases. Phylogenetic analysis of EML1 suggested that the protein belonged to a new family of esterase/lipase together with LipG. The EML1 gene was expressed in Escherichia coli, and purified by metal-chelating chromatography. The optimum activity of the purified EML1 (rEML1) occurred at pH 8.0 and 25 degrees C, respectively, and rEML1 displayed more than 50% activity at 5 degrees C. The activation energy for the hydrolysis of olive oil was determined to be 3.28 kcal/mol, indicating that EML1 is a cold-active lipase. rEML1 preferentially hydrolyzed triacylglycerols acyl-group chains with long chain lengths of > or = 8 carbon atoms and displayed hydrolyzing activities toward various natural oil substrates. rEML1 was resistant to various detergents such as Triton X-100 and Tween 80. This study represents an example which developed a new cold-active lipase from a deep-sea sediment metagenome.
Even though tightened building energy efficiency standards are implemented periodically in many countries, existing buildings continually consume a momentous quota of the total primary energy. Energy efficiency solutions range from material components to bulk systems. A technique of building construction, referred to as prefabricated architecture (prefab), is increasing in reputation. Prefab encompasses the offsite fabrication of building components to a greater degree of finish as bulk building structures and systems, and their assembly on-site. In this context, prefab improves the speed of construction, quality of architecture, efficiency of materials, and worker safety, while limiting environmental impacts of construction, as compared to conventional site-built construction practices. Quite recently, a 57 story skyscraper was built in 19 days using prefabricated modules. From the building physics point of view, the bulk systems and tighter integration method of prefab minimizes thermal bridges. This study seeks to clearly characterize the levels of prefab and to investigate the performance of modular prefab; considering acoustic constrain, seismic resistance, thermal behavior, energy consumption, and life cycle analysis of existing prefab cases and, thus, provides a dynamic case study-based review. Generally, prefab can be categorized into components, panels (2D), modules (3D), hybrids, and unitized whole buildings. On average, greenhouse gas emissions from conventional construction were higher than for modular construction, not discounting some individual discrepancies. Few studies have focused on monitored data on prefab and occupants' comfort but additional studies are required to understand the public's perception of the technology. The scope of the work examined will be of interest to building engineers, manufacturers, and energy experts, as well as serve as a foundational reference for future study.
Two esterase genes (designated as estAT1 and estAT11, respectively) were cloned by activity-based screening of a fosmid library constructed with seashore sediment sample of the Arctic. The sequence analysis of the genes revealed that these esterase genes encoded proteins of 303 and 312 amino acids, respectively, and showed 40-50% identities to members of the hormone-sensitive lipase (HSL) family retaining a catalytic triad with a conserved GDSAG sequence and an oxyanion hole (HGGG). The esterases genes were overexpressed in Escherichia coli by co-expressing GroEL-GroES chaperonine, and the recombinant proteins (rEstAT1 and rEstAT11) were purified to homogeneity. The purified EstAT1 and EstAT11 were active in a broad range of temperature from 20 to 40 degrees C with an optimum temperature at 30 degrees C. The activation energies of rEstAT1 and rEstAT11 to hydrolyze p-nitrophenyl esters of butyrate were determined to be 12.65 kcal/mol and 11.26 kcal/mol, respectively, indicating that they are cold-adapted esterases. The purified EstAT1 and EstAT11 could hydrolyze racemic ofloxacin esters, and further rEstAT11 hydrolyzed preferentially (S)-racemic ofloxacin butyl ester with an enantiomeric excess (ee(p)) value of 70.3%. This work represents an example that develops enzymes from the Arctic using metagenomic approach, potentially applicable to chiral resolution of heat-labile substrates.
Bamboo is a natural building material that can be found in the tropical to mild temperate regions. It has been used from ancient times for its natural strength and flexibility. The renewed interest during the 1980s in bamboo as a construction material has revitalized bamboo not only as a cheap material but also as a durable material. Many bamboo-based building materials have also been developed which is more suitable for the modern construction needs. Bamboo has many environmental benefits which has made it a favorite green building material. This review critically studies not only the environmental aspects when bamboo is used as a building material but also its social and economic aspects, to understand its sustainability impact.
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