A parametric study on supercritical water gasification of Laminaria hyperborea: a carbohydrate-rich macroalga.

The potential of supercritical water gasification (SCWG) of macroalgae for hydrogen and methane production has been investigated in view of the growing interest in a future macroalgae biorefinery concept. The compositions of syngas from the catalytic SCWG of Laminaria hyperborea under varying parameters including catalyst loading, feed concentration, hold time and temperature have been investigated. Their effects on gas yields, gasification efficiency and energy recovery are presented. Results show that the carbon gasification efficiencies increased with reaction temperature, reaction hold time and catalyst loading but decreased with increasing feed concentrations. In addition, the selectivity towards hydrogen and/or methane production from the SCWG tests could be controlled by the combination of catalysts and varying reaction conditions. For instance, Ru/Al2O3 gave highest carbon conversion and highest methane yield of up to 11 mol/kg, whilst NaOH produced highest hydrogen yield of nearly 30 mol/kg under certain gasification conditions

Hydroxyl radical-aided thermal pretreatment of algal biomass for enhanced biodegradability

BACKGROUND: Algal biomass, known as a potential feedstock for biofuel production, has cell wall structures that differ from terrestrial biomass. The existing methods for processing algae are limited to conventional pretreatments for terrestrial biomass. RESULTS: In this study, we investigated a novel hydroxyl radical-aided approach for pretreating different types of algal biomass. In this process, hydroxyl radicals formed by a Fenton system were employed in combination with heating to alter the crystalline structure and hydrogen bonds of cellulose in the algal biomass. FeSO(4) and H(2)O(2) at low concentrations were employed to initiate the formation of hydroxyl radicals. This method releases trapped polysaccharides in algal cell walls and converts them into fermentable sugars. The effects of temperature, time, and hydroxyl radical concentration were analyzed. The optimal pretreatment condition [100 °C, 30 min, and 5.3 mM H(2)O(2) (determined FeSO(4) concentration of 11.9 mM)] was identified using a central composite design. Complete (100 %) carbohydrate recovery was achieved with some algal biomass without formation of inhibitors such as hydroxymethylfurfural and furfural as by-products. Both microalgal and macroalgal biomasses showed higher enzymatic digestibility of cellulose conversion (>80 %) after the milder pretreatment condition. CONCLUSION: Hydroxyl radical-aided thermal pretreatment was used as a novel method to convert the carbohydrates in the algal cell wall into simple sugars. Overall, this method increased the amount of glucose released from the algal biomass. Overall, enhanced algal biomass digestibility was demonstrated with the proposed pretreatment process. The new pretreatment requires low concentration of chemical solvents and milder temperature conditions, which can prevent the toxic and corrosive effects that typically result from conventional pretreatments. Our data showed that the advantages of the new pretreatment include higher carbohydrate recovery, no inhibitor production, and lower energy consumption. The new pretreatment development mimicking natural system could be useful for biochemical conversion of algal biomass to fuels and chemicals. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13068-015-0372-2) contains supplementary material, which is available to authorized users

Form and function of tropical macroalgal reefs in the Anthropocene

1. Tropical reefs have been subjected to a range of anthropogenic pressures such as global climate change, overfishing and eutrophication that have raised questions about the prominence of macroalgae on tropical reefs, whether they pose a threat to biodiversity, and how they may influence the function of tropical marine ecosystems. 2. We synthesise current understanding of the structure and function of tropical macroalgal reefs, and how they may support various ecosystem goods and services. We then forecast how key stressors may alter the role of macroalgal reefs in tropical seascapes of the Anthropocene. 3. High levels of primary productivity from tropical canopy macroalgae, which rivals that of other key producers (e.g., corals, turf algae), can be widely dispersed across tropical seascapes to provide a boost of secondary productivity in a range of biomes that include coral reefs, and support periodic harvests of macroalgal biomass for industrial and agricultural uses. Complex macroalgal reefs that comprise a mixture of canopy and understory taxa can also provide key habitats for a diverse community of epifauna, as well as juvenile and adult fishes that are the basis for important tropical fisheries. 4. Key macroalgal taxa (e.g., Sargassum) that form complex macroalgal reefs are likely to be sensitive to future climate change. Increases in maximum sea temperature, in particular, could depress biomass production and/or drive phenological shifts in canopy formation that will affect their capacity to support tropical marine ecosystems. 5. Macroalgal reefs can support a suite of tropical marine ecosystem functions when embedded within an interconnected mosaic of habitat types. Habitat connectivity is, therefore, essential if we are to maintain tropical marine biodiversity alongside key ecosystem goods and services. Consequently, complex macroalgal reefs should be treated as a key ecological asset in strategies for the conservation and management of diverse tropical seascapes

Bioethanol production from farming non-food macroalgae in Pacific island nations: Chemical constituents, bioethanol yields, and prospective species in the Philippines

Increasing biofuel production on agricultural lands in tropical island nations will likely result in increased deforestation [1], and also inflate food prices, especially in net food importing countries like the Philippines [2], [3] and [4]. Compounding problems associated with promotion of biofuels in southeast Asian countries are the technical efficiencies of bioethanol production, including poor energy balances from terrestrial crops that are close to, or less than unity, unless bagasse is used as the distillation heat source [1]. As the increase in terrestrial biofuel production in Pacific island nations is potentially less sustainable than is publically stated, alternative feedstocks are required which retain the regional development benefits, while reducing the negative ecological and food security impacts [1] and [5]. This work presents the potential of farmed macroalgae chemical substrates as a bioethanol feedstock supply, explores macroalgae-to-bioethanol yields, and details prospective non-food macroalgae species, specific to the Philippine coastal region. Leveraging off the existing capability of the macroalgae farming industry (producing 1.7 million wet tonnes annually in the Philippines alone), a significant new market for non-food macroalgae stimulated by bioethanol producers can be developed to avoid problems related to food/feed grade ethanol feedstocks

Integrated macroalgae production for sustainable bioethanol, aquaculture and agriculture in Pacific island nations

The Philippine Biofuels Act of 2006 mandates domestic gasoline blending with bioethanol at a rate of 5% by 2009 and 2010, and 10% by 2011 (by volume). Akin to most biofuel policies, the Act aims to increase fuel supply security, reduce emissions, and stimulate regional development. However, the majority of biofuels blended are imported due to conventional food market demand for biofuel feedstocks, and limited domestic biofuel production capacity. A promising alternative domestic bioethanol feedstock is macroalgae (seaweed) species, of which the Philippines is already a major global commercial producer. The advantages of using particular non-food macroalgae as a bioethanol feedstock include zero competition with agricultural food production, no freshwater requirement, high yields per area, zero fertilizer applications, and the pre-existing markets for bioethanol macroalgae wastes. Adaptation of existing macroalgae farming methods, customized to high-yielding non-food bioethanol precursor species, can enable rapid expansion into industrial-scale biofuel production, far exceeding terrestrial bioethanol yields in terms of per unit area. This work identifies the regional availability and supply of appropriate macroalgae species suitable for bioethanol production, and explores integrated production synergies and challenges for an environmentally sustainable macroalgae bioethanol industry suitable for a number of Pacific island nations

Theorizing Filipino Pedagogical Beliefs: Narratives of Preservice Elementary Teachers’ Before and After Teaching Immersion

The purpose of this paper is to examine selected preservice elementary teachers' pedagogical beliefs before and after the teaching immersion program using Calderhead's Five Aspects of Pedagogical Beliefs. It aims to uncover meaningful experiences, challenges, and factors that contributed to the change in preservice teachers' pedagogical beliefs. This study employed a qualitative narrative research design with six preservice elementary teachers. The data revealed that the preservice teachers' beliefs significantly changed after the teaching immersion program. The factors contributing to their changes were time constraints, classroom management, and pedagogical responsibilities. However, two factors transcended Calderhead’s framework. Thus, the development of an enhanced framework, Seven Aspects of Pedagogical Beliefs, to include the participants’ beliefs on school culture and mentoring practices. The results of the study provide the pedagogical beliefs, meaningful experiences, challenges, and changes in pedagogical beliefs of pre-service teachers. However, the study is limited to Bachelor of Elementary Education. The study reveals that quality education in teacher education could be furthered through curriculum changes; therefore, it is critical to investigate how pedagogical beliefs influence preservice teachers' classroom decisions. This study uses a qualitative approach to provide a comprehensive picture of preservice teachers' pedagogical beliefs. Given that their beliefs differed before and after their teaching immersion, it is vital to provide new insights into the factors causing this difference

Corn Farmers` Decisionmaking Based on Seasonal Climate Forecasts

Although our ability to predict climate conditions has improved significantly, farmers` use of climate information and forecasts in farming decisions and practices has changed a little. Part of the reasons is the lack of communication of innovations like the seasonal climate forecasts (SCFs). Today, efforts are being initiated to motivate farmers to integrate SCF into their farm decisionmaking. This study was conducted to serve as basis in designing a communication campaign on SCF. Data were gathered in Malaybalay, Bukidnon through focus group discussions, decisionmaking workshops, and interviews with farmers cultivating at least a hectare of corn. In the decisionmaking workshop, farmers were asked to assume hypothetical situations, given a climate forecast for the current years` cropping season, and requested to decide their farming activities based on the climate forecasts. Results showed the popularity of SCF among the farmers. However, farmers depended more on their indigenous climate forecasting than on the SCF. Farmers considered climate forecasts as nonprobabilistic and said that they find it difficult to understand these forecasts. For better understanding, they suggested that climate forecasts use simple words and be downscaled to their locality. Utilizing description-based decisions, their decisions were aimed at maximizing profits and minimizing cost.Philippines, seasonal climate forecast (SCF), climate variability, climate information and corn farming, health workers, corn farmers

Inoculum source of Phytophthora palmivora, jackfruit seedlings health in response to potting media porosity, sanitation, inoculation and phosphonate application

Seedling dieback caused by Phytophthora palmivora (Butler) is a significant problem in jackfruit (Artocarpus heterophyllus Lam.) nurseries in Eastern Visayas, Philippines. It has been linked to insufficient knowledge of inoculum sources and possible factors contributing to seedlings’ health. This study was conducted to identify potential sources of Phytophthora inoculum in representative nurseries in Eastern Visayas and evaluate the effect of possible factors that contribute to seedling health. Phytophthora detection was conducted from random samples of potting media, irrigation water, germination beds, and roots of seedlings from representative nurseries supplying seedlings in the region. Detection was done through tissue baiting and the use of a Phytophthora-specific diagnostic kit. The effect of the air-filled porosity (AFP) of potting media, sanitation, pathogen inoculation, and phosphonate on plant growth and seedlings’ health was evaluated. Phytophthora propagules were positively detected in most samples, suggesting that seedlings most likely already harbor the pathogen when distributed to farms in the region. Among the factors, AFP of the potting medium had the most profound effect on seedlings’ growth and health. The tallest plants with the largest stem diameter, highest dry weight biomass, and least disease rating were grown in the most porous medium (21 % AFP) consisting of 20 % garden soil, 20 % carbonized rice hull, 20 % rice hull, 20 % coco coir dust, 10 % sand, and 10 % chicken dung. The benefit of a highly porous medium was, however, seen only when external fertilization was undertaken. Unsterilized media resulted in healthier seedlings compared to sterilized media. Sterilized potting media that were inoculated with the pathogen after sterilization resulted in more severe disease. Sterilized potting media was beneficial for jackfruit seedlings when supplied with adequate nutrients and as long as contamination with the pathogen does not occur. Sterile media, therefore, should be kept away from recontamination with the pathogen otherwise more severe disease may occur. The addition of the plant defense regulator phosphonate showed no effect on the growth and health of seedlings under the trial’s conditions. © 2021 Society for Advancement of Horticulture. All rights reserved

Jackfruit decline caused by Phytophthora palmivora (Butler)

In the late 1990's a decline syndrome emerged in jackfruit orchards in the Eastern Visayas region of the Philippines. Symptoms included trunk cankers, wilting and dieback of the canopy and, in many cases, tree death. The decline resulted in significant yield losses for farmers. A survey was conducted to assess disease incidence and to identify the causal organism. Fifty two percent of farms surveyed had a disease incidence greater than 50 %. On some farms 100 % of trees were affected. While Fusarium, Pythium, Colletotrichum and Phytophthora species were isolated during disease surveys only Phytophthora was shown to consistently cause decline symptoms in artificially inoculated jackfruit. Healthy jackfruit seedlings, detached leaves and fruit inoculated with Phytophthora isolates expressed similar symptoms to those observed in the field. Based on morphological and molecular characteristics the pathogen was identified as Phytophthora palmivora