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Promoting biodiesel industrialization is not only an important measure in addressing the energy crisis and global warming but is also a driver for industrial restructuring and rural development. To...

Biomass derived from marine microalgae and macroalgae is globally recognized as a source of valuable chemical constituents with applications in the agri-horticultural sector (including animal feeds and health and plant stimulants), as human food and food ingredients as well as in the nutraceutical, cosmeceutical, and pharmaceutical industries. Algal biomass supply of sufficient quality and quantity however remains a concern with increasing environmental pressures conflicting with the growing demand. Recent attempts in supplying consistent, safe and environmentally acceptable biomass through cultivation of (macro- and micro-) algal biomass have concentrated on characterizing natural variability in bioactives, and optimizing cultivated materials through strain selection and hybridization, as well as breeding and, more recently, genetic improvements of biomass. Biotechnological tools including metabolomics, transcriptomics, and genomics have recently been extended to algae but, in comparison to microbial or plant biomass, still remain underdeveloped. Current progress in algal biotechnology is driven by an increased demand for new sources of biomass due to several global challenges, new discoveries and technologies available as well as an increased global awareness of the many applications of algae. Algal diversity and complexity provides significant potential provided that shortages in suitable and safe biomass can be met, and consumer demands are matched by commercial investment in product development.

Abstract In Asia, dry-seeded rice (DSR) production systems are increasing because of water and labour scarcities. DSR can be sown under zero-till (ZT) or after conventional tillage (CONT) operations. In these seeding systems, however, weeds are the main biological constraint. A study was conducted during the wet season of 2012 and the dry season of 2013 at the International Rice Research Institute to evaluate the effect of the tillage systems (ZT and CONT), seeding rate [low seeding rate (LSR) at 50 kg ha−1, and high seeding rate (HSR) at 100 kg ha−1], and weed control treatments (oxadiazon applied as pre-emergence, oxadiazon applied as pre-emergence followed by a commercial mixture of fenoxaprop + ethoxysulfuron as post-emergence at 21–24 days after sowing, and weedy) on weed growth and grain yield in DSR systems. The efficacy of herbicides 14 days after the application of post-emergence herbicide was similar between the tillage systems and between seeding rates. At crop harvest, weed biomass was higher in the ZT plots than in the CONT plots, and higher at LSR than at HSR. At the same time, herbicide applications decreased weed biomass by 73–96%, compared with the weedy plots. Compared with the ZT plots, CONT plots had 9–18% higher grain yield. Similarly, plots sown at HSR had 17–19% higher grain yield than at LSR. Weedy plots had 81–84% less yield than the herbicide-treated plots (3060–3380 kg ha−1 in the wet season and 5820–5950 kg ha−1 in the dry season).

Abstract Despite the remarkable potential for biogas production from livestock and organic wastes, the number of constructed biogas digesters for the continent is in the order of thousands and in case of Mauritania is lower than the number of the provinces. While majority of the existing digesters left far behind the expected efficiency, lack of a comprehensive economic assessment along with an efficient design questions their practical application. The present study introduced the first assessment to evaluate the biogas potential from livestock manures and waste from slaughterhouses in Northwest Africa (a case of Mauritania). Using ArcGIS® software, a database was conducted to build maps that show the amount of waste products, the potential of biogas, and equivalent amounts of energy. These were used to assess the potential of biogas and the corresponding potential energy for each geographical department in Mauritania. The results indicated that the southern provinces had the highest biogas potential with the maximum and the average values of 520 and 258.7 (±125.8) × 106 m3/year. On the other hand, the lowest biogas production potential (27.7 × 106 m3/year) was recorded for northern provinces with the maximum and the average values of 135 and 76.4 (±39.7) × 106 m3/year. The results showed that 63,579 × 106 kg of waste associated with livestock (cattle) and slaughterhouse applications were annually produced in the country. It was determined that this quantity could generate 2451 × 106 m3 of biogas per year, corresponding to an energy potential of 52,704 × 106 MJ/year. Considering the rapid depletion of conventional energy sources and the significance of biogas as a renewable fuel, a detailed feasibility analysis (for the biogas production in each province of Mauritania by means of community type fixed-dome digesters) was also performed in the scope of this study. The results of the comprehensive cost breakdown analysis revealed that the revenues obtained from sale of biogas-generated electricity and digested slurry (as fertilizer) could able to pay the initial investment within approximately 6.5 years without subsidy. The findings of this study, as the first of its own, could be used to comprehend how utilization of information such as slaughterhouse and livestock population, nutrition habitats, land-usage maps and geographic information system (GIS) can be employed to germinate a model for more comprehensive assessment of biogas production potential from livestock manure and slaughterhouse wastes, specifically in case of northern African countries. Moreover, in case of biogas plant, this model could be employed as a decision-making tool to identify the highly qualified location for construction of the biogas plant.

Microbial multispecies ecosystems are responsible for many biotechnological processes and are particularly important in food production. In wine fermentations, in addition to the natural microbiota, several commercially relevant yeast species may be co-inoculated to achieve specific outcomes. However, such multispecies fermentations remain largely unpredictable because of multilevel interactions between naturally present and/or co-inoculated species. Understanding the nature of such interactions has therefore become essential for successful implementation of such strategies. Here we investigate interactions between strains of Saccharomyces cerevisiae and Lachancea thermotolerans. Co-fermentations with both species sharing the same bioreactor (physical contact) were compared to co-fermentations with physical separation between the species in a membrane bioreactor ensuring free exchange of metabolites. Yeast culturability, viability and the production of core metabolites were monitored. The previously reported negative interaction between these two yeast species was confirmed. Physical contact greatly reduced the culturability and viability of L. thermotolerans and led to earlier cell death, compared to when these yeasts were co-fermenting without cell-cell contact. In turn, in the absence of cell-cell contact, L. thermotolerans metabolic activity led to an earlier decline in culturability in S. cerevisiae. Cell-cell contact did not result in significant differences in the major fermentation metabolites ethanol, acetic acid and lactic acid, but impacted on the production of some volatile compounds.

Lead (Pb) is known for its low mobility and persistence in soils. The main aim of the present study was to explore potential of different fungal strains to promote phytoextraction of Pb-contaminated soils. Five non-pathogenic fungal strains (Trichoderma harzianum, Penicillium simplicissimum, Aspergillus flavus, Aspergillus niger, and Mucor spp.) were tested for their ability to modify soil properties (pH and organic matter) and to increase Pb phytoavailability at varying concentrations. Lead tolerance of fungal strains followed the decreasing order as A. niger > T. harzianum > A. flavus > Mucor sp. > P. simplicissimum. Lead solubility induced by A. flavus and Mucor spp. was increased by 1.6- and 1.8-fold, respectively, as compared to the control soil (Pb added, without fungi). A. flavus and Mucor spp. lowered the soil pH by - 0.14 and - 0.13 units, in soils spiked with 2000 mg Pb kg-1. The maximum increase in the percentage of organic matter (OM) recorded was 1.7-fold for A. flavus at 500 mg Pb kg-1 soil. Plant growth-promoting assays confirmed the beneficial role of these fungal strains. Significantly high production of IAA (249 μg mL-1) and siderophores (61%) was observed with A. niger, and phosphate solubilization with P. simplicissimum (58 μg mL-1). Based on the results in Pb-contaminated soils, Pelargonium hortorum L. inoculated with Mucor spp. showed the potential to enhance phytoextraction of Pb by promoting Pb phytoavailability in soil and improving plant biomass production through plant growth-promoting activities.

Abstract The booming seaweed industry in the Philippines has been recently challenged by several problems, including the degrading quality of carrageenan extracts from farmed Kappaphycus species. One emerging concern is the correctness of certain agronomic protocols, specifically the recommended duration of culture of farmed seaweeds. We determined in this study the effect of duration of culture on seaweed biomass and carrageenan quantity and quality of four commercially farmed Kappaphycus species. A mathematical formula was then employed to derive a weekly optimization index (a metric incorporating several parameters or product attributes, viz., biomass, carrageenan yield and gel strength) which was used to determine the appropriate time of harvest. The Kappaphycus species exhibited c. 300% increase in biomass within 4–7 weeks in culture (c. 150 g from an initial biomass of 50 g wet weight) and then a biomass plateau was observed. Carrageenan yield in all seaweeds fluctuated minimally (mean: 55–58%; s.d.: 2–4%), however, gel strength peaked at 8–9 weeks of culture. Highest optimization index was obtained during week 8 for Kappaphycus alvarezii var. alvarezii and week 9 for the rest of the cultured seaweeds (Kappaphycus striatum var. sacol, Kappaphycus sp. “aring-aring” and Kappaphycus sp. “duyan”); hence, the recommended harvest times for the respective seaweeds are during these weeks of culture. As several seaweed manuals recommend other culture durations, a revision of these is appealed in order to safeguard the quality of farmed Kappaphycus species.

Abstract The bio-wastes pyrolysis is a waste to energy strategy that converts bio-wastes into valuable products (bio-char, bio-oil) with wide use in the agri-food sector. However, limited efforts are paid to the investigation of its environmental sustainability: in this context, the study contributes the need towards the assessment of a wide range of environmental impacts for the pyrolysis process of different types of bio-wastes under different operating conditions. The study estimates the potential environmental impacts related to bio-char production from the pyrolysis of several different agro-industrial residues and different temperatures and identifies the process “hot spots”. The analysis is carried out through the life cycle assessment methodology. The functional unit for the analysis is 1 MJ of thermal energy potentially released during the complete combustion of bio-char obtained from the pyrolysis process. The study highlights that, under the examined conditions, the type of biomass affects the environmental impacts of the pyrolysis process more than the peak pyrolysis temperature. Among the biomasses tested, bio-char obtained from orange peels has the lower environmental impacts, with an average percentage difference of about 16% compared to bio-char obtained from olive tree trimmings that has the worst environmental performance. For each biomass, the impacts associated to bio-char obtained with different operational temperatures have percentage differences in general lower than 5%. A contribution analysis shows that the electricity consumed during the operational phase is responsible for the largest impacts in all the examined impact categories, followed by bio-wastes transportation. In detail, the contribution of the electricity to the total impact ranges from minimum values of about 44% (for cumulative energy demand) up to 91% (for terrestrial eutrophication), while transportation contributions range from a minimum of about 4% (for terrestrial and marine eutrophication) to 36% for mineral, fossil and renewable resource depletion. Therefore, the use of more energy efficient processes and technologies and the diffusion of distributed pyrolysis systems near farms can significantly improve the environmental performance of the system examined.