世界経済・社会統計 = World development indicators

https://pubs.rsc.org/en/content/articlepdf/2019/NP/C8NP00092A

Marine natural products.

Genetics and analysis of quantitative traits

As a low-cost adsorbent, biochar can be used as a low-cost adsorbent for wastewater treatment, particularly with respect to treating heavy metals in wastewater. A number of studies have demonstrated effective removal of heavy metals from aqueous solutions by biochar and, in some cases, proven the superiority of biochars to activated carbons. Among several factors affecting the sorption ability of biochars, feedstock materials play a significant role. This review incorporates existing literature to understand the overall sorption behavior of heavy metals on biochar adsorbents. Depending on the biochar type, heavy metal can be removed by different mechanisms such as complexation, physical sorption, precipitation and electrostatic interactions. Mathematical sorption models can be used to understand the efficiency of biochar at removing heavy metals, and promote the application of biochar technology in water treatment.

A review of biochar as a low-cost adsorbent for aqueous heavy metal removal

Global demand for macroalgal and microalgal foods is growing, and algae are increasingly being consumed for functional benefits beyond the traditional considerations of nutrition and health. There is substantial evidence for the health benefits of algal-derived food products, but there remain considerable challenges in quantifying these benefits, as well as possible adverse effects. First, there is a limited understanding of nutritional composition across algal species, geographical regions, and seasons, all of which can substantially affect their dietary value. The second issue is quantifying which fractions of algal foods are bioavailable to humans, and which factors influence how food constituents are released, ranging from food preparation through genetic differentiation in the gut microbiome. Third is understanding how algal nutritional and functional constituents interact in human metabolism. Superimposed considerations are the effects of harvesting, storage, and food processing techniques that can dramatically influence the potential nutritive value of algal-derived foods. We highlight this rapidly advancing area of algal science with a particular focus on the key research required to assess better the health benefits of an alga or algal product. There are rich opportunities for phycologists in this emerging field, requiring exciting new experimental and collaborative approaches.

https://link.springer.com/content/pdf/10.1007%2Fs10811-016-0974-5.pdf

Algae as nutritional and functional food sources: revisiting our understanding

The optimised reduction of dissolved nutrient loads in aquaculture effluents through bioremediation requires selection of appropriate algal species and strains. The objective of the current study was to identify target species and strains from the macroalgal genus Ulva for bioremediation of land-based aquaculture facilities in Eastern Australia. We surveyed land-based aquaculture facilities and natural coastal environments across three geographic locations in Eastern Australia to determine which species of Ulva occur naturally in this region and conducted growth trials at three temperature treatments on a subset of samples from each location to determine whether local strains had superior performance under local environmental conditions. DNA barcoding using the markers ITS and tufA identified six species of Ulva, with U. ohnoi being the most common blade species and U. sp. 3 the most common filamentous species. Both species occurred at multiple land-based aquaculture facilities in Townsville and Brisbane and multiple strains of each species grew well in culture. Specific growth rates of U. ohnoi and U. sp. 3 were high (over 9% and 15% day(-1) respectively) across temperature treatments. Within species, strains of U. ohnoi had higher growth in temperatures corresponding to local conditions, suggesting that strains may be locally adapted. However, across all temperature treatments Townsville strains had the highest growth rates (11.2-20.4% day(-1)) and Sydney strains had the lowest growth rates (2.5-8.3% day(-1)). We also found significant differences in growth between strains of U. ohnoi collected from the same geographic location, highlighting the potential to isolate and cultivate fast growing strains. In contrast, there was no clearly identifiable competitive strain of filamentous Ulva, with multiple species and strains having variable performance. The fast growth rates and broad geographical distribution of U. ohnoi make this an ideal species to target for bioremediation activities at land-based aquaculture facilities in Eastern Australia.

/pdf/algal-bioremediation-of-waste-waters-from-land-based-1uzp0t883w.pdf

Algal bioremediation of waste waters from land-based aquaculture using ulva: selecting target species and strains.

Seaweed cultivation is a high growth industry that is primarily targeted at human food and hydrocolloid markets. However, seaweed biomass also offers a feedstock for the production of nutrient-rich biochar for soil amelioration. We provide the first data of biochar yield and characteristics from intensively cultivated seaweeds (Saccharina, Undaria and Sargassum – brown seaweeds, and Gracilaria, Kappaphycus and Eucheuma – red seaweeds). While there is some variability in biochar properties as a function of the origin of seaweed, there are several defining and consistent characteristics of seaweed biochar, in particular a relatively low C content and surface area but high yield, essential trace elements (N, P and K) and exchangeable cations (particularly K). The pH of seaweed biochar ranges from neutral (7) to alkaline (11), allowing for broad-spectrum applications in diverse soil types. We find that seaweed biochar is a unique material for soil amelioration that is consistently different to biochar derived from ligno-cellulosic feedstock. Blending of seaweed and ligno-cellulosic biochar could provide a soil ameliorant that combines a high fixed C content with a mineral-rich substrate to enhance crop productivity.

/pdf/biochar-from-commercially-cultivated-seaweed-for-soil-4s17ttel5d.pdf

Biochar from commercially cultivated seaweed for soil amelioration

The green seaweeds Derbesia tenuissima and Ulva ohnoi were assessed comparatively for yields of biomass and bioproducts (fatty acids, soluble fibres and amino acids) under controlled land-based culture over 6 months. The intensive cultivation of these seaweeds yielded an average biomass productivity of 15 g dry weight (dw) m−2 day−1 (56 t dw ha−1 year−1) for D. tenuissima and 38 g dw m−2 day−1 (138 t dw ha−1 year−1) for U. ohnoi. The production of D. tenuissima was comparatively consistent, ranging between 8 and 20 g dw m−2 day−1, while that of U. ohnoi was highly variable and stochastic, ranging between 16 and 77 g dw m−2 day−1. The major bioproducts were lipids (13 % dw) and fatty acids (5 % dw) for D. tenuissima and soluble fibres (ulvan, 12 % dw) for U. ohnoi. These concentrations were consistent over time, irrespective of the variation in environmental conditions and biomass productivity. In addition, D. tenuissima and U. ohnoi are potential bioresources for the extraction of proteins (amino acids). The amino acid content of D. tenuissima (24 % dw) was higher than that of U. ohnoi (13 % dw). However, the annual amino acid productivity of U. ohnoi (18 t ha−1 year−1) was higher than that of D. tenuissima (14 t ha−1 year−1) due to the higher annual productivity of biomass. Notably, both species offer niche opportunities to deliver multiple products through a biorefinery process.

The intensive land-based production of the green seaweeds Derbesia tenuissima and Ulva ohnoi: biomass and bioproducts

Algae represent a promising target for the generation of bioenergy through slow pyrolysis, leading to the production of biochar. This study reports experiments conducted on the production of freshwater and saltwater macroalgal biochar in pilot-scale quantities, the physical and chemical characteristics of the biochars, and their impact on plant growth. The biochars are low in carbon (C) content, surface area and cation exchange capacity, while being high in ash and nutrients. Trace element analysis demonstrates that macroalgal biochar produced from unpolluted water does not contain toxic trace elements in excess of levels mandated for unrestricted use as a biosolids amendment to soils. Pot trials conducted using a C and nutrient-poor soil, without and with additional fertilizer, demonstrate dramatic increases between 15 and 32 times, respectively, in plant growth rate for biochar treatments compared with the no biochar controls, with additional smaller increases when fertilizer was added. Pot trials conducted using a relatively fertile agricultural soil showed smaller but significant impacts of biochar amendment over the controls.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1757-1707.2011.01109.x

Algal biochar: effects and applications

Asparagopsis taxiformis has potent antimethanogenic activity as a feed supplement at 2 % of organic matter in in vitro bioassays. This study identified the main bioactive natural products and their effects on fermentation using rumen fluid from Bos indicus steers. Polar through to non-polar extracts (water, methanol, dichloromethane and hexane) were tested. The dichloromethane extract was most active, reducing methane production by 79 %. Bromoform was the most abundant natural product in the biomass of Asparagopsis (1723 μg g−1 dry weight [DW] biomass), followed by dibromochloromethane (15.8 μg g−1 DW), bromochloroacetic acid (9.8 μg g−1 DW) and dibromoacetic acid (0.9 μg g−1 DW). Bromoform and dibromochloromethane had the highest activity with concentrations ≥1 μM inhibiting methane production. However, only bromoform was present in sufficient quantities in the biomass at 2 % organic matter to elicit this effect. Importantly, the degradability of organic matter and volatile fatty acids were not affected at effective concentrations.

Nicholas A. Paul

Papers

Algal bioremediation of waste waters from land-based aquaculture using ulva: selecting target species and strains.

Biochar from commercially cultivated seaweed for soil amelioration

The intensive land-based production of the green seaweeds Derbesia tenuissima and Ulva ohnoi: biomass and bioproducts

Algal biochar: effects and applications

Identification of bioactives from the red seaweed Asparagopsis taxiformis that promote antimethanogenic activity in vitro