Short term effects of irradiance on the growth of Pterocladiella capillacea (Gelidiales, Rhodophyta)

Pterocladiella capillacea has been economically exploited for agar extraction in the Azores for many years. Harvesting dropped to a full stop in the early 1990s due to a population collapse, but restarted in 2013. Since then it has been intensively harvested and overexploitation must be prevented, with both sustainable harvesting and effective cultivation practices. This study represents the first attempt to determine optimal conditions for P. capillacea production in the Azores, and evaluates its vegetative growth in two experiments using von Stosch’s medium designed to test entire thallus and tips portions response to different irradiances (30, 70 and 150 μmol photons m¯² s¯¹). The best relative growth rate (RGR) was recorded at 150 μmol photons m¯² s¯¹ for the entire thalli and tips after two-weeks and three-weeks, respectively, indicating that an acclimation period is necessary to assure the growth of this alga under experimental conditions. Higher RGR was obtained at higher irradiance (3.98 ± 2.10% fm day¯¹), but overall, growth rates were low or negative. Epiphytes were a serious problem towards the end of the entire thallus experiments, where Feldmannia irregularis proliferate at all irradiances. Future cultivation approaches complemented with other relevant environmental factors (e.g. pH, photoperiod, salinity), are recommended.FCT – Fundação para a Ciência e Tecnologia projects UID/BIA/00329/2013, 2015 - 2018 and UID/BIA/00329/2019, CIRN (Centro de Investigação de Recursos Naturais, University of the Azores), and CIIMAR (Interdisciplinary Centre of Marine and Environmental Research, Porto, Portugal). RFP was supported by a doctoral grant M3.1.2/F/024/2011, Fundo Regional para a Ciência e Tecnologia.info:eu-repo/semantics/publishedVersio

Multiresponsive spiropyran-based copolymer: synthesis and characterization

Photochromic copolymers carrying spiropyran side groups have attracted particular attention for potential applications in optical devices, photonic memory and photosensing, as well as, fluorescence imaging.[1] These materials allow overcoming many of the limitations inherent to traditional spiropyran doped polymers, such as, phase separation of the colorant and retardation of the decoloration of the open form.[2] The introduction of light sensitive moieties within responsive polymers has led to the development of sophisticated multiresponsive systems.[3] Block copolymers are important self-assembling systems that can assume a diversity of nanometer-scale morphologies due to the incompatibility and the connectivity constrains between the chemically distinct segments. Therefore, self-assembly of photochromic copolymers in the solid state or in solution allows the development of nanostructured materials. [4] The aim of this research study is the synthesis of a multiresponsive spiropyran-based copolymer, poly(styrene)- co-poly([1´,3´,3´-trimethyl-6-methacryloyloxyspiro(2H-1-benzopyran-2,2´-indoline)]4-vinylbenzoic acid) 2. The functionalized block copolymer poly(styrene)-block-poly(4-vinylbenzoic acid) (PSt-b-P4VBA) 1 synthesized by reversible addition fragmentation chain-transfer (RAFT) polymerization was coupled with 1,3,3-trimethyl-6- hydroxyspiro(2H-1-benzopyran-2,2-indoline). The link between the functionalized block copolymer and spiropyran was successfully obtained by Steglich esterification using DMAP/DCC as catalysts (Scheme 1).n-STeP ProjectNORTE-07-0124-FEDER-000039Programa Operacional Regional do Norte (ON.2)PEst-C/CTM/LA0025/2013 (Strategic Project - LA 25 - 2013-2014

Effect of clay mineral addition on properties of bio-based polymer blends

The effect of clay mineral addition to bio-based blends on morphology and physical properties of thermoplastic starch (TPS) and polypropylene grafted with maleic anhydride (PP-g-MA) was investigated. Blends and nanocomposites containing organoclay, Cloisite 30B, were prepared by melt mixing and characterized by several techniques. X-ray diffraction (XRD), scanning and transmission electron microscopy (SEM, STEM) and dynamic mechanical analysis (DMA) demonstrate a very good dispersion of the clay mineral in the polymer matrix, an increase of polymer compatibility and an improvement of mechanical properties. Biodegradation studies performed in compost revealed that Cloisite 30B addition enhanced the matrix biodegradability. Therefore clay minerals, which can be obtained from natural resources, can be efficiently used to improve the properties of bio-based materials and contribute to sustainability.The authors acknowledge the n-STeP - Nanostructured systems for Tail, with reference NORTE-07-0124-FEDER-000039, supported by the Programa Operacional Regional do Norte (ON.2), PEst-C/CTM/LA0025/2013 (Strategic Project - LA 25 - 2013-2014)

Design of a Continuous Improvement Model in a Portuguese Food Industry Company – A Case Study

The search for perfection forces organizations to adopt new techniques and approaches, focused on the systematic creation of innovative solutions that facilitate the processes of continuous improvement. In view of this context, there was an opportunity to study the implementation of the Lean philosophy in the production line, at a processed food organization. A continuous improvement model was designed for an organizational system, combining tools used in both TRIZ methodology and Lean philosophy. Several Lean tools are used in the model in order to support problem formulation, e.g. Brainstorming, 5 Whys, Pareto Diagram, Ishikawa Diagram, Plan-Do-Check-Act (PDCA) Cycle. And the Kano Model integrated in the proposed model allows assessing employee satisfaction at a later stage than the implementation of previously found solutions. In case the problems identified are not very complex, were resorted to the use of both TRIZ and Lean techniques, such as cause/effect databases, the 40 problem solving TRIZ principles, visual management, 5S's or line balancing. But if the problems identified are more complex, which means with an inventive issue to be solved, Matrix of Contradictions and S-Field Analysis TRIZ tools proved to be more appropriate to find the proper solution. With the case study carried out, it was noted that the proposed model proved to be very useful as a roadmap for the implementation of Lean and TRIZ tools in the continuous improvement of industrial products, services and processes should be the ways to continually minimize them in a company.authorsversionpublishe

Thermoplastic starch-polypropy/lene reinforced with clay

In this study, bio-based blends of thermoplastic starch (TPS) and polypropylene grafted with maleic anhydride (PP-g-MA) without and with organoclay, Cloisite 30B, were prepared in an internal mixer. A TPS-g-PP copolymer was successfully obtained in melt and its formation was confirmed by SEM. The establishment of this copolymer creates an interpenetrating network leading an intercalated/exfoliated clay nanocomposite. Several analytical, angle X-ray diffraction (XRD), scanning and transmission electron microscopy (SEM, STEM) and dynamic mechanical analysis (DMA) were used to characterize the prepared materials. The nanocomposites mechanical properties were improved, showing an increase of about 11% for the nanocomposite when compared with the neat blend. Biodegradation studies performed in compost revealed good percentage of weight loss for the copolymer with clay addition

Development of silver and clay-starch bio-nanocomposites

Starch, among biopolymers is that had the lowest production cost, wide availability, fully biodegradability and is a renewable agriculture resource. Starch due to its sensitivity to humidity and poor mechanical properties cannot be used in many applications. For that, the dispersion of clays in this material improves their physical and mechanical properties, at very low filler loadings. On the other hand, the incorporation of silver nanoparticles into biocompatible and biodegradable matrices gives antimicrobial properties opening a new field for packaging applications. [...

Effect of nitrogen limitation on starch accumulation in Chlorella vulgaris

Due to the limited stocks of fossil fuels and the production of greenhouse gas carbon dioxide on their combustion alternative sources of energy are being investigated. Recently, microalgae have received much attention as a renewable energy resource because these photosynthetic microorganisms can convert sunlight, water and CO2 into potential biofuels (1). The microalga Chlorella vulgaris, particularly, has been considered as a potential raw material for bioethanol production because it can accumulates high levels of starch when grown under optimized culture conditions (2). The aim of the present work was to study the effect of nitrogen limitation on starch production by the microalgae C. vulgaris. C. vulgaris CCAP 211/1e (P12 strain) was obtained from the Culture Collection of Algal Laboratory, Institute of Botany, Academy of Sciences of the Czech Republic. The original (nitrogen sufficient) growth medium based on the elementary composition of algal biomass had the following initial composition (mg l−1): 1,100 (NH2) 2CO, 237 KH2PO4, 204 MgSO4∙7H2O, 40 C10H12O8N2NaFe, 88 CaCl2, 0.83 H3BO3, 0.95 CuSO4∙5H2O, 3.3 MnCl2∙4H2O, 0.17 (NH4) 6Mo7O24∙4H2O, 2.7 ZnSO4∙7H2O, 0.6 CoSO4∙7H2O, and 0.014 NH4VO3 in distilled water (3). Nitrogen limited growth medium was formulated by omitting urea from the original growth medium. The microalgae were grown in 1 l Schott flasks with 0.4 l of medium. Cultures were maintained at 30ºC under continuous, cool white fluorescent lamps. Light intensity was approximately 100 mmol m‐2 s‐1 at the surface of the photobioreactors. The concentration of suspended algal biomass was determined by optical density measurement at 700 nm. Starch content in the microalgae was determined colorimetrically by the anthrone reaction. The results showed that starch accumulation in C. vulgaris was strongly related to nitrogen concentration. Under nitrogen limited growth conditions, starch constituted 36% of the algal biomass after 118 h of cultivation, whereas nitrogen sufficient microalgae contained 8% of their dry weight as starch. On the other hand, nitrogen sufficient condition led to an increase in biomass concentration, with the highest biomass concentration of 2.06 g l‐1. It can be concluded that accumulation of starch is enhanced in nitrogen limited cultures of C. vulgaris P12

Mixotrophic cultivation of Chlorella vulgaris using industrial dairy waste as organic carbon source

Growth parameters and biochemical composition of the green microalga Chlorella vulgaris cultivated under different mixotrophic conditions were determined and compared to those obtained from a photoautotrophic control culture. Mixotrophic microalgae showed higher specific growth rate, final biomass concentration and productivities of lipids, starch and proteins than microalgae cultivated under photoautotrophic conditions. Moreover, supplementation of the inorganic culture medium with hydrolyzed cheese whey powder solution led to a significant improvement in microalgal biomass production and carbohydrate utilization when compared with the culture enriched with a mixture of pure glucose and galactose,due to the presence of growth promoting nutrients in cheese whey. Mixotrophic cultivation of C.vulgaris using the main dairy industry by-product could be considered a feasible alternative to reduce the costs of microalgal biomass production, since it does not require the addition of expensive carbohydrates to the culture mediumThis study was supported by the grants SFRH/BD/44724/2008 (Bruno Fernandes) and SFRH/BPD/44935/2008 (Giuliano Dragone) from Fundacao para a Ciencia e a Tecnologia (Portugal). The authors also acknowledge the financial support received through the projects INNOVALGAE (FCT PTDC/AAC-AMB/108511/2008) and ALGANOL