22 research outputs found
Finishing the euchromatic sequence of the human genome
The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead
Polymer templated nickel cobaltate for energy storage★
In order to take advantage of the increasing sophistication of technology for harnessing renewable energy resources, serious attention must be paid to how to store and re-access this energy. Electrochemical storage, in the guise of batteries, supercapacitors and pseudocapacitors, has attracted much attention as a viable option for enhanced energy storage applications. But in order for these technologies to be implemented successfully we need to find materials that perform better and are relatively easy to synthesise. Bimetallic transition metal oxides are materials that are readily synthesised and may be multifunctional, i.e. have a role at the electrochemical atomic level as well as the device level. In order for these materials to work efficiently in new generation systems based on sodium and lithium they also need to be mesoporous. This can be achieved by trying to find synthetic techniques that produce specific, highly regulated nanostructures or by adding a ‘templating’ agent during the bulk synthesis step. We have investigated the simple hydrothermal preparation of a number of nickel cobaltate (NiCo2O4) materials using polymer templates, eggshell membrane (ESM) and poly methyl methacrylate (PMMA), as potential electrode materials for supercapacitors. The ESM was expected to act as a fibrous, random polymeric template while the PMMA should produce a much more ordered material. Electrochemical testing showed that the different templates have led to changes in material morphology and these have resulted in a difference in electrochemical properties. Templated materials increased specific capacitance compared to non-templated and the choice of template could influence the capacitance by as much as 30%
Sustainable phycocyanin production from Arthrospira platensis using solar-control thin film coated photobioreactor
Solar irradiance consists of photosynthetically-active photons that can be transformed to valuable biomolecules by microalgae. Light also has undesirable non-photosynthetic photons, such as ultraviolet and infrared wavelengths that heat up algal closed photobioreactors above optimum temperatures for growth. In this study, a solar control infrared blocking film (IRF) is applied to an algal flat plate photobioreactor to block excessive non-photosynthetic photons and regulate the temperature profile of Arthrospira platensis cultures for the production of C-phycocyanin (C-PC). The performance of the IRF is compared against other cooling mechanisms such as insulated-glazed photovoltaic (IGP), conventional water-jacket (CWJ) and a no heat control (NHC) photobioreactors. Experimental results show that the maximum temperature (30.94 ± 0.09 °C) in the IRF culture is only 5% higher than that in CWJ culture but 33% lower than that in NHC cultures. No significant differences were found in C-PC content or biomass productivity when Arthrospira is grown using IGP, CWJ or IRF but is significantly lower in NHC photobioreactors. Chlorophyll a fluorescence probing of A. platensis shows that IRF, IGP and CWJ cultures are not thermally stressed, however, NHCs cultures are highly stressed due to supraoptimal temperatures. Our results clearly indicate that solar control film is a potential tool for blocking non-photosynthetic photons and managing culture temperature in flat plate photobioreactors for sustainable C-phycocyanin production from A. platensis
Can solar control infrared blocking films be used to replace evaporative cooling for growth of Nannochloropsis sp. in plate photobioreactors?
Photobioreactor overheating is a significant challenge of microalgal mass production, resulting in low photosynthetic efficiency and poor biomass productivity. Due to cost and performance limitation, passive evaporative cooling systems for managing culture temperature are currently neither economical nor sustainable. In this study, the growth and photophysiology of Nannochloropsis sp. MUR 267 in four different flat plate photobioreactors designs, namely, solar control infrared reflecting film (IRF), insulated glazed photovoltaic (IGP), conventional water jacket (CWJ), and no heat control (NHC), were evaluated. Maximum attained culture temperature in the IRF is comparable with CWJ and 22.6% lower than NHC. Biomass productivity in the IRF (112.47 ± 3.36 mg·L −1 ·d −1 ) is only 10% lower than that attained in the CWJ, and no net growth was seen in the NHC due to a high temperature. The immediate vitality of the cell photosynthetic apparatus monitored diurnally through the effective quantum yield of photosystem II (F q ’/F m ’) showed values \u3e 0.6 in IRF, CWJ and IGP. This study showed that clear infrared blocking films can significantly reduce the heat in PBRs without a dramatic reduction in culture performance. © 2019 Elsevier B.V
Co-Producing Phycocyanin and Bioplastic in <i>Arthrospira platensis</i> Using Carbon-Rich Wastewater
Microalgae can treat waste streams containing elevated levels of organic carbon and nitrogen. This process can be economically attractive if high value products are created simultaneously from the relatively low-cost waste stream. Co-production of two high value microalgal products, phycocyanin and polyhydroxybutyrate (PHB), was investigated using non-axenic Arthrospira platensis MUR126 and supplemental organic carbon (acetate, oxalate, glycerol and combinations). All supplemented cultures had higher biomass yield (g/L) than photoautotrophic control. All cultures produced PHB (3.6–7.8% w/w), except the control and those fed oxalate. Supplemented cultures showed a two to three-fold increase in phycocyanin content over the eight-day cultivation. Results indicate co-production of phycocyanin and PHB is possible in A. platensis, using mixed-waste organic carbon. However, supplementation resulted in growth of extremophile bacteria, particularly in cultures fed glycerol, and this had a negative impact on culture health. Refinement of the carbon dosing rate is required to minimise impacts of native bacterial contamination