Search

To minimize the cost of algae-based biofuels and bioproducts, boosting biomass productivity and enhancing the stability of cultures in outdoor cultivation systems are imperative. Strain improvement strategies, mainly adaptive evolution, random mutagenesis, and genetic engineering, focus on perturbing the metabolism of algae to develop desired phenotypes. However, the aforementioned techniques are time- and labor-intensive with a possibility of reversion of the mutated/adapted phenotypes back to wild type. In this regard, the chemical genetics approach has emerged as a rapid and powerful approach to preferentially direct the metabolism of algae towards desired target products with the incorporation of small chemical modulators in a dose-dependent manner. In this review, we critically asses the use of chemical modulators to tweak the metabolism of several algal species and enhance biomass production, bioproduct yield, and resilience to abiotic stressors. The review highlights important categories of chemical modulators and the techniques employed to identify and screen such small effective molecules. Chemical modulators enable the re-design and fine-tuning of targeted algal metabolic pathways rendering chemical genetics a promising approach for enhancing algal productivity particularly in large-scale cultivation. • Use of chemical modulators helps generate desired algal phenotypes. • High throughput screening can identify potential chemical modulators. • Phytohormones, amino acids, inhibitors, and metabolites boost algal productivity. • Exogenous addition of chemical modulators alleviates oxidative stress in algae. • Chemical genetics can facilitate development of algal biofuels and bioproducts. [ABSTRACT FROM AUTHOR]

• RUSLE has been coupled with the MAGNET model to estimate the global economic impacts of soil erosion. • The estimated annual cost to global GDP is eight billion US dollars. • Global agri-food production is reduced by 33.7 million tonnes. • Abstracted water volumes are driven upwards by an estimated 48 billion cubic meters. • Soil erosion accelerates shifts in comparative advantage on world agri-food markets. Employing a linkage between a biophysical and an economic model, this study estimates the economic impact of soil erosion by water on the world economy. The global biophysical model estimates soil erosion rates, which are converted into land productivity losses and subsequently inserted into a global market simulation model. The headline result is that soil erosion by water is estimated to incur a global annual cost of eight billion US dollars to global GDP. The concomitant impact on food security is to reduce global agri-food production by 33.7 million tonnes with accompanying rises in agri-food world prices of 0.4%–3.5%, depending on the food product category. Under pressure to use more marginal land, abstracted water volumes are driven upwards by an estimated 48 billion cubic meters. Finally, there is tentative evidence that soil erosion is accelerating the competitive shifts in comparative advantage on world agri-food markets. [ABSTRACT FROM AUTHOR]

• Assessment of food waste reduction impact needs to include economic and biophysical indicators. • Economy-wide models as proposed in this paper can account for all market and non-market impacts of reducing food waste. • Reducing households' food waste increases savings; it decreases agri-food production and to a minor extent GDP. • Environmental indicators are improving as EU land use, water abstraction and greenhouse gas emissions decline. Halving per capita food waste and reducing food losses along production and supply chains is one of the objectives fixed by the United Nations among the Sustainable Development Goals (SDGs). This study employs a system-wide modelling approach, to simulate economic impacts of households' food waste reduction in 2030, focusing on the European Union. The paper provides market, food security, biophysical and environmental indicators resulting from food commodity specific waste reductions by EU households. The scenarios explicitly account for associated costs paid by food manufacturers derived from adjustments in the packaging, labelling and logistics. The model shows, under a series of market assumptions, a possible increase in household savings, a fall in agri-food production and a minor negative macroeconomic impact due to household food waste reductions. On the other hand, the effects on environmental indicators such as land usage, GHG emissions and water abstraction are positive. Future research on several aspects of the food waste topic is needed to better integrate all economic aspects. [ABSTRACT FROM AUTHOR]

Modeling and optimization of key design parameters of bioreactors are critical for development of economically and technically viable algae technologies. The objective of this study is to use computational fluid dynamics (CFD) modeling to design a novel enclosed Horizontal BioReactor (HBR) equipped with a paddle wheel that incurs low capital and operating costs like raceway ponds, but achieves high productivities like enclosed photobioreactors. For the HBR the aspect ratio (length-to-width), paddle wheel diameter and positioning, culture depth, and baffle spacing can be manipulated to achieve adequate flow of the culture that minimizes the formation of low-velocity areas, below 20 cm/s, termed “dead zones”. The CFD procedure focused on minimizing dead volume and power consumption. A small-scale HBR (3 m 2 of surface area) was used for development and validation of the hydrodynamic model, whose parameters were calculated using experimental data. The model was then applied to a pilot-scale HBR (40 m 2 ) that is operated outdoors. Placing the paddle wheel at either end of the reactor or incorporating baffles minimized the dead volume. The same effect was also achieved by increasing the size of the paddle wheel or the number of paddle wheels or the depth of the culture. On the other hand, increasing the reactor's aspect ratio resulted in more dead volume, although it decreased power consumption. These findings will be incorporated into the design of large-scale HBRs (200 m 2 ) for commercial deployment. [ABSTRACT FROM AUTHOR]

Originally conceived as a post-war policy vehicle for ensuring agricultural self-sufficiency, the Common Agricultural Policy (CAP) has evolved into a multifunctional instrument designed to satisfy a diverse portfolio of European Union (EU) policy objectives including nature protection. Notwithstanding, whilst the CAP has become more environmental and socially responsible, it is still expected to deliver an efficient farm production system capable of competing on world markets. The current paper combines a farm business panel dataset for 98 EU territories with a Stochastic Frontier Analysis (SFA) approach, to assess the impact of four contemporary broad categories of CAP subsidy programs on efficiency and environmental sustainability. In accordance with the literature, this study more correctly defines inputs as “facilitating”, whilst following recent methodological developments, crop-subsidies are treated as an endogenous strategic variable in the production function. Comparing between two discrete time periods, further tests are conducted to examine the hypothesis of technical efficiency convergence across european territories. The results suggest that first pillar crop subsidies and pillar two environmental programs generate a disincentive effect on productivity, whilst in general, the CAP promotes technical efficiency convergence within Europe. [ABSTRACT FROM AUTHOR]

We employ a heavily modified 'agricultural' variant of the GTAP model and a realistic baseline scenario to assess the impact on the Greek economy from a hypothetical 'hub and spoke' and a 'FTA' EUMED agro-food and fisheries trade agreement. Long run estimates show that Greek agro-food and fisheries sectors are not seriously affected, where surprisingly, trade diversionary losses to Greece from the FTA scenario are minor given minimal south-south trade links between Mediterranean Partner Countries (MPC). Further research shows that under complete CAP decoupling, notable additional welfare gains for MPC are realised, whilst Greece stands to lose approximately €300 million. [ABSTRACT FROM AUTHOR]

Hydrothermal carbonization converts algal biomass to hydrochar, but also generates a waste aqueous phase rich in nitrogen and other elements that need to be treated before discharge into water bodies. At the same time, cultivation of microalgae requires significant amounts of nutrients, such as nitrogen, phosphorous, and trace metals. Utilization of aqueous phase in algae cultivation can potentially reduce algae production cost, while mitigating waste generation, leading to a circular process that enhances the sustainability of algal biofuels and bioproducts. In the present study, we assessed the potential of aqueous phase generated during hydrothermal carbonization of lipid-extracted algae to support algal biomass and lipid production from Chlorella vulgaris. The aqueous phase was found to contain high concentrations of nitrogen (2.4 g/L), phosphorus (1.75 g/L), organic carbon (20.9 g/L), and trace elements. Among several aqueous phase dilutions in non-sterilized water (2.5–7.5% v/v) tested for algae cultivation, maximum lipid productivity that was 1.7-fold higher than with standard cultivation media was achieved when C. vulgaris was grown in 5% aqueous phase. Time course studies showed significant nutrient removal of 95% nitrate, 60% ammonia, 47% phosphate, and 30% organic carbon by C. vulgaris over the course of a 10-day cultivation. Moreover, when compared with standard media, utilization of the aqueous phase resulted in augmentation of both storage and structural algal lipids that can be used for biofuel and nutraceutical production, respectively. Subsequent bench-top photobioreactor cultivation validated that the aqueous phase is a promising cultivation medium for algal product manufacturing. [Display omitted] • Chlorella vulgaris tolerated up to 7.5% aqueous phase (AP) in water. • Optimal lipid productivity, achieved in 5% AP, exceeded that in standard media. • AP enhanced synthesis of phospholipids and neutral lipids. • AP from hydrothermal carbonization is an effective nutrient source for algae. [ABSTRACT FROM AUTHOR]

The repertoire of novel biobased materials is continually expanding as they represent green alternatives to carbon-intensive fossil materials. Lipid-extracted algae (LEA) biomass is a promising feedstock for the production of a spectrum of biobased materials, such as hydrochar and biochar, electrodes in microbial fuel cells (MFCs), supercapacitors, biocomposites, biopolymers, activated carbon including N-doping, and biosorbents. By selecting appropriate process conditions, these renewable products can be designed to possess desirable properties and, at the same time, be more sustainable. Most importantly, we view LEA as a potentially significant additional source of revenue for algae biorefineries that can accelerate the commercial development of algae. The present study assesses the utilization of LEA for the production of biobased materials, their applications and sustainability profile, and future trends. [Display omitted] • Lipid-extracted algae (LEA) biomass is converted to biobased materials. • LEA biomaterials are tailored to possess desirable properties. • Converting LEA to valuable products can enhance the economics of algae technologies. • LEA biomaterials can enhance sustainability. [ABSTRACT FROM AUTHOR]

• The impact of healthy diets to 2050 is examined within a global simulation model. • The baseline exposes regional 'pressure points' for virtual commodity consumption. • Diet change drives global falls (rises) in agricultural land and GHGs (water) consumption. • Sub-Saharan Africa benefits from a "rebound¨ effect due to cheaper meat and dairy prices. • The healthy diet switch requires an increase in per capita expenditure world wide. The importance of healthy diets is woven into the fabric of the Sustainable Development Goals, although there is no clear metric to define it. Employing a simulation model (MAGNET), this study examines the sustainability implications arising from the adoption of recommended daily nutrition requirements inspired by the 'Lancet' reference diet. To measure sustainability, changes in 'virtual' requirements and associated tier footprints for irrigation (blue) water, agricultural land and greenhouse gas emissions (GHG) are calculated. Assuming business-as-usual food consumption trends, between 2015 and 2050 blue water, agricultural land and emissions rise 34%, 9% and 44%, respectively, whilst corresponding increases in Sub-Saharan Africa are much higher. By 2050, the switch to the reference diet decreases agricultural land use by -8% and emissions by -9%. Global blue water and cropland requirements increase by 5%, whilst significant concomitant savings in permanent pastureland (-21%) are expected. By region, the diet switch drives rising blue water consumption in Oceania and the EU and agricultural land savings in Latin America and Oceania, accompanied by cropland increases in the EU and North Africa. The reference diet generates substantial reductions in GHG emissions, particularly in Latin America. Interestingly, Sub-Saharan Africa which abstains from the reference diet due to affordability considerations, benefits from a 'rebound' effect from falling meat and dairy prices. Finally, the diet shift could result in marginal per capita food expenditure rises arising from demand driven fish price, particularly in more vulnerable world regions. This estimate does not capture, however, second-round economic growth effects arising from increased labour productivity and reduced public health expenditures. [ABSTRACT FROM AUTHOR]

Concerns about greenhouse gas emissions and climate change have raised global demand for renewable products, leading to increased interest in sustainable resources. Microalgae constitute a potentially sustainable source of natural compounds, such as phospholipids, which are extensively used in cosmetics as part of liposomes, emulsifiers, solubilizers, and wetting agents. Currently phospholipids are extracted from food sources, a practice that raises sustainability concerns. Photosynthetic microalgae cultivated on nitrogen and phosphorus macronutrients may serve as a more sustainable source of the major phospholipids phosphatidylcholine, phosphatidylethanolamine, lyso-phosphatidylcholine, and lyso-ethanolamine. We assessed the effect of nitrogen and phosphorous provision on phospholipid production by the marine microalga Nannochloropsis oculata cultivated in a 3.5-liter flat panel photobioreactor at two macronutrient mass ratios, NO 3 −/PO 4 3− = 15 and NO 3 −/PO 4 3− = 5. Using organic solvent extraction and 31P NMR spectroscopy, phospholipid content in cell mass was found to be 26% higher at the ratio of 5 than at the ratio of 15, indicating that phosphate-rich cultivation boosts phospholipid formation. Moreover, the specific growth rate of the culture at the ratio of 5 was higher than at the ratio of 15. After the growth phase the cultures were subjected to macronutrient starvation, a common practice for increasing total lipid production. Therefore, maintaining a NO 3 −/PO 4 3− ratio of 5 is deemed to be essential for exploiting microalgae for large scale production of phospholipids. Unlabelled Image • Nannochloropsis oculata produced phospholipids, a cosmetics ingredient. • The macronutrient ratio NO 3 −/PO 4 3− affected algal productivity during cultivation. • At the phosphorus-rich ratio of 5, cell growth was faster than at 15. • At the phosphorus-rich ratio of 5, phospholipid content was 26% higher than at 15. • A NO 3 −/PO 4 3− ratio of 5 is essential for large scale production of phospholipids. [ABSTRACT FROM AUTHOR]