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Colloidal solutions of silver nanoparticles (AgNPs) were synthesized by gamma Co-60 irradiation using different stabilizers, namely polyvinyl pyrrolidone (PVP), polyvinyl alcohol (PVA), alginate, and sericin. The particle size measured from TEM images was 4.3, 6.1, 7.6, and 10.2 nm for AgNPs/PVP, AgNPs/PVA, AgNPs/alginate, and AgNPs/sericin, respectively. The influence of different stabilizers on the antibacterial activity of AgNPs was investigated. Results showed that AgNPs/alginate exhibited the highest antibacterial activity against Escherichia coli (E. coli) among the as-synthesized AgNPs. Handwash solution has been prepared using Na lauryl sulfate as surfactant, hydroxyethyl cellulose as binder, and 15 mg/L of AgNPs/alginate as antimicrobial agent. The obtained results on the antibacterial test of handwash for the dilution to 3 mg AgNPs/L showed that the antibacterial efficiency against E. coli was of 74.6%, 89.8%, and 99.0% for the contacted time of 1, 3, and 5 min, respectively. Thus, due to the biocompatibility of alginate extracted from seaweed and highly antimicrobial activity of AgNPs synthesized by gamma Co-60 irradiation, AgNPs/alginate is promising to use as an antimicrobial agent in biomedicine, cosmetic, and in other fields.

In the search for new and renewable energy, Gracilaria sp. was studied as the raw material for bioethanol production. This seaweed is available abundantly in the very long Indonesian coastline. This study investigates the effect of several pretreatment methods on the concentration of sugar produced from Gracilaria sp. when hydrolyzed using cellulase or sulphuric acid. Reducing sugar was measured by UV-Vis spectrophotometry using Nelson-Somyogi reagent and the ethanol concentration was measured by using gas chromatography. Cellulase and sulphuric acid (H2SO4) were used in the hydrolysis. Cellulase concentration used was 200, 400, 600 and 800 units/ml, whereas the concentration of sulphuric acid used was 1%, 3%%, 5%, and 7%. The highest concentration of reducing sugar was produced by hydrolysis using H2SO4 1%.

The Department of Energy’s Bioenergy Technology Office (BETO) collaborates with a wide range of institutions towards the development and deployment of biofuels and bioproducts. To facilitate this effort, BETO and its partner national laboratories develop detailed techno-economic assessments (TEA) of biofuel production technologies as part of the development of design cases and state of technology (SOT) analyses. A design case is a TEA that outlines a target case for a particular biofuel pathway. It enables preliminary identification of data gaps and research and development needs and provides goals and targets against which technology progress is assessed. On the other hand, an SOT analysis assesses progress within and across relevant technology areas based on actual experimental results relative to technical targets and cost goals from design cases and includes technical, economic, and environmental criteria as available.

BETO also develops supply chain sustainability analyses (SCSA) for key biofuel production technologies that are the subject of design case or SOT analyses (Dunn et al. 2013). The SCSA utilizes a life-cycle analysis to estimate the energy use and greenhouse gas (GHG) emissions associated with biofuel production and assists in comparing several biofuel pathways. This report documents an SCSA of whole algae hydrothermal liquefaction (AHTL) as the conversion technology to produce renewable diesel (RD). Jones et al. (2014) developed the design case process model that provides the material and energy intensity of the feedstock conversion step in the SCSA.

The SCSA production stages for microalgae-derived RD are presented in Figure 1. Various inputs (red boxes) can be considered for each supply chain step (green boxes). These inputs can include energy, fertilizers for biomass growth, and any materials that may be needed during the conversion process. The major environmental output from the system is GHG emissions, which come from direct sources like fuel combustion during a processing step or indirect sources like fertilizer production. Another common output is coproducts, which can be used to displace materials or energy from other production processes. There can be difficulties in allocating emissions to these co-products (Wang et al., 2011), so care is needed during their consideration.

The SCSA for RD produced via AHTL starts with feedstock production, which requires nutrients (fertilizers), water (not considered in this study), and energy in the form of electricity and other fuels, e.g., natural gas. After production, the feedstock is transported to the conversion facility, or biorefinery, using energy in the form of a transportation fuel. In the case of microalgae, cultivation ponds are assumed to be co-located with the conversion facility (Davis et al., 2012; Frank et al., 2011) meaning a transportation fuel is not required. However, energy is needed for pumping the biomass from the harvesting units to the biorefinery. For the algae-to-RD production reported here, the harvested feedstock goes to a thermal conversion process, which includes material inputs like catalysts and sulfuric acid. A small amount of naphtha, which was treated as a liquid fuel, is produced along with RD in the AHTL pathway. No other co-products are produced in the fully integrated AHTL algae-to- RD pathway. The total supply chain emissions burdens were allocated to total fuel produced, including naphtha and RD.

The renewable fuel, after the conversion process, is transported to a fueling station by train, barge, and truck. The biogenic CO2 released when the fuel is combusted balance out with the atmospheric CO2 that the algae incorporated when it was growing (Frank et al., 2011). The emissions described above are the so-called, “fuel cycle” emissions. Emissions are also associated with the construction of the plant (Canter et al., 2014). These “infrastructure cycle” emissions were estimated in this study.

The MacroFuels project aims to advance the technologies for producing liquid transportation biofuels from cultivated seaweed (or macroalgae), thereby providing a sustainable solution for the provision of transportation fuels for heavy goods transport and the aviation sector.

Seaweeds are amongst the fastest growing plants in the world, producing large quantities of biomass over a short timespan. They do this without the use of fresh water, fertilizers, pesticides, and farmland, that are all needed for land-based cultivation. In order to grow, seaweed needs only carbon dioxide (CO2), sunlight and the nutrients already present in the ocean.

To validate the benefits of the seaweed biofuel concept and, ultimately, to provide a basis for the development of incentivising policies, a sustainability assessment is an integral part of the MacroFuels project. The assessment is a multi-criteria appraisal that evaluates the impacts of seaweed-derived transport fuels with respect to the environment and society and their technical and economic viability, as well as health, safety and risk aspects of the seaweed biofuel production system.

These different pillars of sustainability are assessed in individual work tasks. In order to facilitate the integrated sustainability assessment, to ensure consistency and to allow for consolidation and overall conclusions to be drawn, it is necessary that each work task is conducted on the basis of common criteria, where this is possible and appropriate. To this end, this report:

 Defines the approach taken for the integrated sustainability assessment;

 Presents the results of an integrated sustainability assessment of the MacroFuels concept; and

 Provides options to improve the sustainability performance of the MacroFuels concept.