Sustainable Alternative Sources Research Articles

Biotechnological applications of Clostridium thermocellum and Bacillus coagulans

Clostridium thermocellum and Bacillus coagulans both bacteria hold commercial biotechnological importance because of their capability to produce numerous industrial products such as Clostridium thermocellum due to its cellulose fermenting capability are used either as pure or as co–cultures to produce alternative sustainable energy sources such as biofuels including bioethanol, biogas, organic acid, acetic acid derivatives.

Production of lipids and proteins from marine diatoms under changing pH and silica

Diatom algae are increasingly explored as an alternative sustainable source for functional biomolecules likes fucoxanthin, and eicosapentaenoic acid. But biomolecule quantity and quantity are influenced by growth conditions. So, effect of differential silica concentration (0–120 mg L-1) and medium pH (5.5–9.5) on growth and cellular biochemical composition of commercially important marine diatom species were studied. Growth rate of Thalassiosira sp., Skeletonema sp., and Chaetoceros sp., was higher with 30 mg L-1 Si at a pH of 7.5–8.5. Highest carbohydrate (153.71 mg g−1) and protein (17.34 mg g−1) content was found in Skeletonema sp. Silica concentration positively influenced chlorophyll and carotenoid content in a dose dependent manner. A medium pH of 8.5 and Si concentration between 60 and 120 mg L-1 was ideal for lipid production. The optimum concentration of Si and pH for maximum biomolecule production have been reported with further scope of utilizing these conditions in commercial scale systems.

Informal artisanal and small-scale gold mining (ASGM) in Ghana: Assessing environmental impacts, reasons for engagement, and mitigation strategies

The informal artisanal and small-scale mining (ASGM) sector in Ghana has been engrossed with grave environmental challenges and practices. Whereas some ideologies call for its perpetual banning, others believe efficient reformation of the sector is rather required. This study sought to assess the impacts of informal ASGM on the environment and the root causes of why these illegal mining activities are very prevalent after several attempts to formalize or ban them. It further sought to assess the mitigation measures to reduce their footprint for sustainable mineral extraction. A semi-structured interview guide, field observations, and sampling were used to obtain relevant data for further analysis. Results indicated that informal ASGM had detrimental impacts on water and soil resources. Although the miners were aware of the detrimental effects of their activities, the desire for basic life necessities for their families and survival remained their priority than the conservation of the environment. It was further revealed that the lack of sustainable alternative sources of livelihood, the general economic hardship and unemployment, the “quick and easy” way of making money in informal ASGM, and the political influence in the sector remains a major driving force for illegal mining in Ghana. So far as the cost of “action” on sustainable practices in ASGM is comprehended more than the benefits of reducing the adverse impacts, interventions for better practices will not be supported even at the government level. Purely political solutions will not fix what is basically an economic problem. This study, therefore, calls for broader and continual stakeholder engagements in developing workable policies that will not seek to outrightly criminalize informal mining but help improve it. This study recommends that informal ASGM should be harnessed to bring economic prosperity to stakeholder's rather than to be treated as an evil venture. The provision of sustainable alternative jobs, preferably in the mining sector, is encouraged to help reduce active participation in this illicit activity. Right technological, finance, and technical skills investments can be key to achieving this.

Tuning the Polarity of Dinitrile-Based Electrolyte Solutions for CO2 Electroreduction on Copper and Copper-Based Catalysts

Accumulating carbon dioxide (CO2) concentrations in the atmosphere due to anthropogenic sources has become an increasing threat to the environment because of the resulting effects of global warming. It has therefore become imperative to develop and utilize alternative sustainable sources for fuels and feedstock chemicals. CO2 electrochemical reduction (CO2ER) has been identified as a promising process which can convert CO2 to added value chemicals, such as hydrocarbons. In combination with the use of renewable energy resources, the technology has potential to be a net zero carbon process. Commonly, aqueous electrolytes are used for the reaction such as bicarbonate or phosphate-buffered saline solutions. However, these exhibit low CO2 solubilities, which hinders the performance of the reaction by limiting mass transfer. Organic solvent electrolytes possess relatively higher CO2 solubilities. These are also able to suppress the competing hydrogen evolution reaction (HER) due to lowered proton concentrations. Organic nitrile-solvent-based electrolytes, more commonly studied for Li-ion batteries, are known to possess high thermal and electrochemical stability. Furthermore, the polarity and CO2 miscibility can be tuned in dinitrile solvents by variation of the chain length. As such, the effect of chain length was explored on organic dinitrile-based solvent electrolytes for the application of CO2 electroreduction. The selected dinitrile solvents were Adiponitrile (n=4), Suberonitrile (n=6), and Sebaconitrile (n=8), where n indicates the number of methylene groups in the chain. These dinitriles were also compared to Acetonitrile, a commonly used organic mononitrile solvent. Conductivity was first studied as a function of salt concentration and temperature for all solvents. Then, CO2 solubility was evaluated for the different solvents. Finally, electrochemical tests utilizing copper and copper-based bimetallic catalysts were conducted. The catalysts explored consisted of synthesized copper (I) oxide (Cu2O) and copper-silver (CuAg) nanoparticles, obtained through a chemical reduction method in water using sodium borohydride (NaBH4) at ambient conditions. These particles were evaluated against commercial Cu2O and CuAg nanoparticle counterparts. The Cu-based nanoparticles were characterized using XRD, TEM, EDX, and EELS techniques. The obtained results are summarized and discussed.

Response of peanut (Arachis hypogaea L.) plant to bio-fertilizer and plant residues in sandy soil

Nitrogen (N) fertilizer has been intensively used to improve peanut productivity. However, the high cost of N fertilizer, and the need for sustainable alternative fertilizer sources have increased the strategic importance of nitrogen fixation (NF). Thus, field experiments were conducted in an experimental farm with a drip irrigation system, at the Atomic Energy Authority, Inshas, Egypt, in order to measure the impact of efficiency symbiotic Bradyrhizobium sp. and asymbiotic Azotobacter sp. on NF, from air and soil, in the presence or absence of plant residues on the growth and yield of peanut plant. All treatments received nitrogen fertilizer at a rate of 72 kg N per hectare. Nitrogen dose was applied using ammonium sulphate 15N labeled of 10% atom excess from the peanut. Results indicated that the application of Bradyrhizobium sp. with plant residues significantly increased fresh and dry weight/m2, pod and seed weight/plant−1,100- seed weight, and biological yield kg ha−1, where the highest mean values of seed yield (4648 and 4529 kg ha−1), oil % (52.29 and 52.21%), seed protein percentage (16.09 and 15.89%), as well as nitrogen derived from air (63.14 and 66.20%) in the first and second seasons were recorded under the application of Bradyrhizobium sp, respectively. Bradyrhizobium sp. inoculation showed nearly close portions of Ndfa to those recorded with Azotobacter sp., in both the presence and absence of plant residue application through the two seasons. The investigated yield signs and their properties were significantly enhanced by bacterial inoculation with plant residue application. The present study shows that both possibility of NF of peanut, and nitrogen uptake in the soil are enhanced by field inoculation with effective Bradyrhizobium sp. with plant residue application. In practice, inoculation is a great strategy to improve soil fertility for subsequent planting, since it helps boost the import of nitrogen from plant biomass into the soil.

Effect of Covid-19 Pandemic to the Fishers in a Coastal Municipality in the Philippines

The fishing industry was not spared by threats of Covid-19 pandemic, despite being considered as part of essential industry. This study determined the effects of the pandemic to the fishing industry, particularly the fishers, in terms of their cost of operation, sales and volume of catch. It also identified their problems encountered and the strategies used to deal with the problems. The study employed descriptive quantitative research design. Respondents, who are the local fishers in a coastal municipality of Bulan, Sorsogon, Philippines, are randomly chosen through stratified random sampling. Survey questionnaire was used and data were analyzed through descriptive statistics. Results revealed that respondents had been heavily affected by the pandemic, particularly in their cost of operation among the three areas of concern. This was due to increase in prices of crude oil/gasoline, food commodities, and fishing gears and equipment. Only few respondents, however, expressed that there are effects on sales and volume of catch. Findings of the study revealed that most common problems were price increase in gasoline/crude oil and fishing gears, as well as price volatility of fish. Study found that respondents took loans (from loan sharks/brokers), repaired their fishing gears by themselves (instead of buying or paying for repair) and attend more to their alternative source of income, to overcome the challenges of pandemic to their livelihood. It recommends that local government must consider providing fishers with relief/loan assistance, particularly during state of calamities, as well as providing livelihood programs and skills training for more sustainable alternative source of income.

Replacement of fish meal with fermented plant proteins in the aquafeed industry: A systematic review and meta‐analysis

AbstractIn the aquaculture feed industry, fishmeal is widely used as a source of animal protein due to its high palatability, excellent amino acid profile and increased digestibility. However, the incorporation of fishmeal in aquaculture diets increases the costs of production due to the declining wild fish stocks hence an urgent need to search for sustainable and cheaper alternative protein sources. The use of fermented plant proteins as substitutes for fishmeal in aquaculture diets has recently gained attention due to their improved nutritional quality, easy availability and low costs. Therefore, a systematic review and meta‐analysis were conducted to quantify the effects of fermented plant proteins as substitutes for fishmeal on the growth performance, feed utilisation, survival, antioxidant, metabolic and digestive enzyme activity of several aquaculture species. Results of the meta‐analysis indicated that replacement of fishmeal with fermented plant proteins in aquaculture diets enhanced the growth performance, feed utilisation, antioxidant and digestive enzyme activities of several aquaculture species regardless of experimental duration and source of fermented plant protein. Likewise, metabolic enzyme activity (i.e., Alanine aminotransferase and Aspartate aminotransferase) was reduced in experimental dietary treatment groups relative to the fishmeal control groups. To elucidate the influence of moderators on the observed effect sizes, a mixed‐effects model was conducted and the results indicated that fishmeal substitution levels and aquaculture species influenced the observed effect sizes in both antioxidant and digestive enzyme activity. No significant differences were noted in survival between the experimental dietary treatment groups and fishmeal control diets among all aquaculture species. However, carnivorous marine species exhibited lower values for specific growth rate and protein efficiency ratio in experimental dietary treatment groups compared to the fishmeal control diets. Likewise, freshwater species exhibited poor FCR values in experimental dietary treatment groups relative to the fishmeal control diets. Overall, the replacement of fishmeal with fermented plant proteins in aquaculture diets is a safe and viable solution for increased and sustainable aquaculture production.

Rooftop rainwater harvesting for sustainable water usage in residential buildings for climate resilient city building: case study of Rajshahi, Bangladesh

PurposeThe effects of population growth in the developing world and climate change have increased the stress on available water resources. The majority of Rajshahi city, Bangladesh, is facilitated with groundwater withdrawal. As Bangladesh is a country of monsoon climate, reserved rainwater can be contributed as an alternative to extracted groundwater. This study aims to develop a framework for rooftop rainwater harvesting (RRWH) for domestic purposes and estimate the appropriate size of the storage tanks and their costs required to fulfill the annual drinking and cooking water demands through RRWH in Rajshahi city of Bangladesh.Design/methodology/approachA total of 100 single-story residential dwellings with varying rooftop areas were surveyed for the projection of RRWH potential. The relationship between the size and cost of a water tank and the rooftop areas of different houses is expressed using a general mathematical equation. Cost estimates for the proposed RRWH system for all houses have been completed, and a cost model illustrating the relationship between rooftop or catchment area and associated cost of RRWH system has been developed.FindingsThis study reveals that a maximum of 110.75 m3/year rainwater can be collected from a 100 m2 rooftop area of Rajshahi city. Moreover, this study finds that such harvesting of rainwater can reduce municipal water supply to the extent of almost 75%. Water samples collected from rooftops also revealed that if germs were removed through bacteria treatment, the collected rainwater potentially can be used for drinking and cooking purposes.Originality/valueThe novelty of this study is that it focused mainly on how significant RRWH can be to meet people’s daily required amount of water for household purpose and ascertain the cost reduction using the RWH method. This paper also is unique as it assessed the volume of the storage tank that is sufficient to distribute the necessary amount of water for drinking and cooking purpose as a sustainable alternative source in the dry season.

Extraction, characterisation and functional applications of sustainable alternative protein sources for future foods: A review

• Alternative protein sources are viewed to be more sustainable than animal proteins. • Potential replacers for animal proteins need to have similar functional properties. • There are opportunities and challenges of incorporating alternative proteins in food processing and manufacturing. • Food waste needs to be addressed as key to food security. For many centuries, animal proteins have been used as the conventional food proteins in the food industry to produce a variety of food products due to their functional properties that range from gelation, water holding and binding capacity, foaming ability and stability, solubility, and emulsification. However, the production of proteins from animal sources does come at a cost due to its impact on the environment. Thus, the search for potential replacers for animal proteins that are sustainable, cheaper, and environmentally friendly has resulted in the exploration and the incorporation of alternative proteins in different food product formulations. Even though studies have been carried out to investigate the functional properties of several alternative protein sources, there are technological, sensorial, and nutritional challenges that still need to be overcome in order to make alternative protein sources a more feasible exchange for animal-based proteins. Additionally, the impact of processing on the functional and structural characteristics of alternative proteins in addition to the health impact still need to be understood. Therefore, this review discusses alternative protein sources that have been researched and documented as potential substitutes for animal-based protein sources. The extraction, characterisation, functional properties, and the nutritional quality of alternative proteins in comparison to the conventional animal-based protein sources will also be discussed. Additionally, this review aims to highlight opportunities and challenges of incorporating alternative proteins in food processing and manufacturing.

Thermal, structural, and rheological modifications in recycled polyethylene terephthalate for a sustainable alternative source for additive manufacturing

AbstractThis work reports the thermal, rheological, and crystallographic structural behavior of recycled polyethylene terephthalate (rPET) derived from bottle waste. The intent is to optimize it to an upcoming source for additive manufacturing by modulating its behavior using a chain extender triphenyl phosphite (TPP), nanofiller montmorillonite (MMT K‐10), and catalyst antimony trioxide (Sb2O3). FT‐IR (Fourier Transform Infrared) analysis showed an increase in absorbance due to the Sb2O3. The thermal analysis of the rPET using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) ascertains a 10°C decrease in Tg with a substantial increase in the degradation onset of 7°C due to MMT content. The melt flow index (MFI) study showed an increase with a similar range in intrinsic viscosity and weight average molecular weight (Mw) due to the additives. The percentage crystallinity, interlayer distance, and average crystallite size are determined and analyzed by X‐ray diffraction (XRD) and DSC curves. The results are within the comparative range of both tests. The presence of Sb2O3 with higher MMT content showed agglomeration, and increased TPP showed low crystalline properties. These results provide that rPET can be altered to manufacture feedstock to suit different 3D printing techniques for prototyping.

Partial Substitution of Fish Oil with Microalgae (Schizochytrium sp.) Can Improve Growth Performance, Nonspecific Immunity and Disease Resistance in Rainbow Trout, Oncorhynchus mykiss.

Simple SummaryThe global price of fish oil continued to increase due to a consistent downward production trend. Therefore, research on the replacement of fish oil is growing and the search for sustainable alternative sources in aquaculture. The present study was conducted to evaluate dietary microalgae, Schizochytrium sp. (SC) as fish oil replacer in rainbow trout, Oncorhynchus mykiss. Our results suggested that dietary SC is well-digested and could replace up to 80% of fish oil in the diet of rainbow trout without negative effects on growth and immune responses.The price of fish oil has reached a historical peak due to a consistent downward production trend, and therefore, the search for sustainable alternative sources has received great attention. This research was conducted to evaluate dietary micro-algae, Schizochytrium sp. (SC) as fish oil (FO) replacer in rainbow trout, Oncorhynchus mykiss. In the first trial, apparent digestibility coefficient (ADC) was 92.4% for dry matter, 91.4% for crude protein, and 94.2% for crude lipid in rainbow trout. In the second trial, six diets were formulated to replace FO at 0% (CON), 20% (T20), 40% (T40), 60% (T60), 80% (T80), and 100% (T100) with SC in the rainbow trout (3.0 ± 0.4 g, mean ± SD) diet. After eight weeks’ feeding trial, weight gain (WG), specific growth rate (SGR), and feed efficiency (FE) of fish fed the T20 diet were significantly higher than those of fish fed other diets (p < 0.05). However, there were no significant differences in these parameters among those of fish fed CON, T40, T60, and T80 diets. Lysozyme activity of fish fed the T20 diet was significantly higher than those of fish fed other experimental diets (p < 0.05). After 10 days of disease challenge testing with pathogenic bacteria (Lactococcus garvieae 1 × 108 CFU/mL), the cumulative survival rate of fish fed the T20 diet was significantly higher than those of fish fed the CON, T80, and T100 diets. Therefore, these results suggest dietary microalgae SC is well-digested and could replace up to 80% of fish oil in the diet of rainbow trout without negative effects on growth and immune responses.

Protein Kaynağı Olarak Böcekler

The world population growth has increased demand for traditional protein sources but an alternative protein source was sought due to limited land. Edible insects containing all the essential amino acids in a healthy diet are sustainable and promising alternative protein source. The protein content of insects varies in a wide range depending on the type of insect and the stage of development (13%-77%). Some edible insects are currently consumed by two billion people worldwide. In the literature, more than 2100 insect species have been recorded as edible. The sensory attributes of edible insects are an important factor that can accelerate their acceptance by consumers. Generally, the taste of insects is described as nutty and largely depends on the cooking technique. Potential food safety risks of edible insects can be microbiological, parasitological and allergenic. This review has been shown to be a healthy food source with high protein content, lipids, vitamins, minerals and fiber, the nutritional composition and functionality are compared between different insect species, and information on the sensory quality and risks of insect eating is presented.

MICROALGAE BIOMASS PRODUCTIVITY BY CO2 INJECTION IN CORRELATION WITH pH VARIATION IN PHOTOBIOREACTOR

Microalgae can bring solution for reducing CO2 and as alternative sustainable energy source. CO2reduction by microalgae was done by fi xation of CO2 during photosynthesis while they grow. The objectiveof the study is to get pH condition from CO2 injection into cultivated microalga that gives better productivityof biomass. Microalga that used was Scenedesmus.sp. Scenedesmus.sp did grown better in Walne media onlab scale experiments. CO2 injection as pH control that gave the highest dry weight obtained on pH rangevalue 7.0-7.5. As one of the controlling factor that determines the biological ability of microalgae in utilizingnutrient, pH value shows that at range of pH 8.0 – 8.5 and 9.0 – 9.5 can decrease photosynthetic process onmicroalgae Scenedesmus.sp Thus the highest fi xated CO2 also on pH value 7.0 – 7.5. This research give abrief explanation that in the range of pH 7.0 – 7.5 contain more CO2 than range pH 8.0 – 8.5 and 9.0 – 9.5.Culture temperature did not show any high fl uctuation at morning and in the mid-day of treatment.

Development and Characterization of Thai Fish Cake (Tod Mun Pla) Fortified with Sago Palm Weevil Larvae (Rhynchophorus ferrugineus)

Edible insects are promoted as new alternative sustainable sources of food. However, consumption is still limited to specific groups of consumers because of food neophobia and unwillingness to eat insects. One of the techniques that can alleviate the neophobia is to process edible insects into familiar foods. Thus, the aim of this study was to develop and characterize Thai fish cake (Tod mun pla, TFC) fortified with sago palm weevil larvae (Rhynchophorus ferrugineus) (SPWL). Different ratios of fish mince: sago palm weevil at 100:0, 80:20, 60:40, 40:60, 20: 80, (w/w), were investigated. The breaking force, deformation and gel strength of TFC increased (P&lt;0.05) while the expressible moisture content (P&lt;0.05) decreased when the ratio of SPWL was increased. Texture profile analysis (TPA) of TFC was improved when low levels of SPWL were added, particularly at the treatment of 80:20 (P&lt;0.05). The color of TFC intensified when fortified with SPWL (P&lt;0.05). Oily characteristics of TFC were observed with SPWL incorporation at a higher level as indicated by stereomicroscope, a result which was concomitant with the greater fat content (P&lt;0.05). Fortifying the TFC with SPWL at the ratio of 80:20 (w/w) provided the highest sensory acceptance for all attributes amongst all treatments. However, higher ratios of SPWL had a negative effect on sensory acceptance. Therefore, TFC fortified with SPWL at an appropriate level could reduce food neophobia and increase sensory acceptance.

Bacterial Composition of Scotophilus kuhlii Guano from Plant Roost around Rice Farms in South-central Mindanao, Philippines

Conventional farming relies on the heavy application of synthetic agrochemicals, especially fertilizers. Thus, the search for an alternative sustainable source of safe agricultural inputs is imperative. Bat guano is an organic material that improves plant growth due to its rich chemical content and associated beneficial microorganisms. However, farmers still have a negative perception towards its utilization due to its associated microbiological hazards and limited supply. This study was conducted to determine the bacterial composition of guano produced by Scotophilus kuhlii to elucidate the potential benefits and hazards it poses when utilized as a soil amendment. The bacterial composition of a 24-h-old guano was investigated by sequencing the amplified 16S rRNA gene under Illumina MiSeq 250 PE system. A total of 78,670 valid DNA reads were obtained and clustered to 196 operational taxonomic units (OTUs). Eight bacterial phyla were identified dominated by Proteobacteria (40.52%), Bacteroidetes (21.43%), Actinobacteria (21.15%), and Firmicutes (16.58%). Under these phyla, 85 genera were identified dominated by Acinetobacter (32.16%), Sphingobacterium (12.94%), and Glutamicibacter (12.25%). Among all generated OTUs, 39 species were identified dominated by Dietzia cinnamea (19.91%), Spingobacterium multivorum (14.65%), Acinetobacter variabilis (14.57%), and Enterococcus faecalis (13.51%). The study revealed that guano of S. kuhlii harbors a diverse bacterial community, which could be a determinant of its usability as an organic soil amendment. Despite the presence of plant- growth promoters and biodegraders of hazardous environmental contaminants, the abundance of Proteobacteria indicates a high number of pathogenic species in the fresh guano. The results suggest the importance of crafting safety guidelines and protocols for guano processing that apply to small-scale farming to maximize the agricultural benefits of guano while reducing the risks imposed by its associated pathogenic bacteria.

Recognizing Potential Pathways to Increasing the Consumption of Edible Insects from the Perspective of Consumer Acceptance: Case Study from Finland

Mitigating the sustainability challenges related to agriculture and ensuring adequate availability of nutritious food requires an increase in the use of sustainable alternative protein sources. Edible insects are considered to be a sustainable protein source and a possible substitute for meat. There are many readily available edible insect species with many competing utilization possibilities, which, from the producers’ perspective, increases the complexity of the area. Through a consumer survey and expert interviews, this study recognizes four pathways to increasing the use of edible insects in Western countries and especially in Finland where the survey and interviews were conducted: (1) producing a variety of insect-based food products, especially food products where insects are not recognizable as such and the food is in a familiar form; (2) producing edible insect food products which could replace greenhouse gas emission-intensive animal proteins; (3) focusing on the price, taste, and availability of insect food; and (4) using insects as animal feed. Our findings provide information on the prospects of the studied pathways in terms of consumption and production. Technological development is expected to decrease the price of insect-based food products, but at the same time, the increased use of edible insects faces challenges related to eating habits, contradictory perceptions about the sustainability implications of insect farming, and the availability of insect-based products.

Evaluating the potential for utilising migratory locust powder (Locusta migratoria) as an alternative protein source in peanut-based ready-to-use therapeutic foods.

This study aimed at exploring the possibility of substituting powdered milk (PM) with migratory locust powder (MLP) as a cheap and sustainable alternative protein source in peanut-based ready-to-use therapeutic foods used in treatment of malnutrition. The migratory locust is a wide spread and underutilised high protein edible insect. Peanut-based ready-to-use therapeutic foods (RUTFs) were formulated according to the MSF/UNICEF 2013 nutritional standards. Milk powder was substituted with MLP at 5-30% levels. RUTF containing 30% milk powder was used as the control. Nutritional, antioxidant and antinutrients composition of the insect-enriched RUTFs were compared with RUTF containing milk powder only and a standard. The protein content of the insect-enriched RUTFs ranged from 19.58-26.38% exceeding the MSF/UNICEF minimum standard for protein. RUTF with 10% PM and 20% MLP had the highest (p < 0.05) mineral contents. All formulations had more thiamine (vitamin B1) than the recommended level of 0.5 mg/100 g. Niacin (Vitamin B3) was the most abundant vitamin in the formulations with considerable amounts of vitamin D and E. All MLP-enriched RUTFs met the FAO 2011 standard requirements for amino acids for children aged six months to three years. Therapeutic food with 30% MLP had the highest radical scavenging ability against DPPH, and iron chelating activity. Levels of phytate and tannin were below the tolerable limits. Therefore, MLP can be used as a low-cost substitute for milk powder in producing ready-to-use therapeutic foods.

Isolation of omega-3 polyunsaturated fatty acids (eicosapentaenoic acid - EPA and docosahexaenoic acid - DHA) from diatom biomass using different extraction methods

The long chain omega-3 polyunsaturated fatty acids are essential for the proper functioning of human body. With an increasing demand for such products, an evaluation on the use of alternative sustainable sources of omega-3 fatty acids becomes extremely relevant. The present study concerned the isolation of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) from diatom biomass by different extraction methods. The first step concerned the optimization of the analysis method based on high-performance liquid chromatography - diode array detector (HPLC-DAD), and the evaluation of corresponding validation parameters. The developed method provided adequate limits of detection and quantitation, as well as appropriate criterion for reproducibility and linearity. Biomass samples harvested from cultures of Pseudostaurosira trainorii were pre-treated and submitted to Soxhlet extraction using methanol-chloroform, reflux extraction with acetone and supercritical fluid extraction (SFE) using 96% ethanol as co-solvent. Prior analysis, the extracts were subjected to derivatization process utilizing 2,4′-dibromoacetophenone in acetone andtriethylamine. The yielded derivatives were analyzed by HPLC-DAD and concentrations of EPA and DHA recovered from dry biomass were determined. The greatest content of omega-3 fatty acids was obtained for reflux extraction (EPA – 63.746 mg g−1, DHA – 1.379 mg g−1), followed by Soxhlet method (EPA – 39.729 mg g−1, DHA – 1.059 mg g−1) and SFE extraction (EPA – 33.701 mg g−1, DHA – 0.455 mg g−1). Although a lower fraction of fatty acids was recovered by using SFE, the obtained extracts present lower toxicity and may be directly applied to the development of daily products.

From Waste to Watts: Updates on Key Applications of Microbial Fuel Cells in Wastewater Treatment and Energy Production

Due to fossil fuel depletion and the rapid growth of industry, it is critical to develop environmentally friendly and long-term alternative energy technologies. Microbial fuel cells (MFCs) are a powerful platform for extracting energy from various sources and converting it to electricity. As no intermediate steps are required to harness the electricity from the organic substrate’s stored chemical energy, MFC technology offers a sustainable alternative source of energy production. The generation of electricity from the organic substances contained in waste using MFC technology could provide a cost-effective solution to the issue of environmental pollution and energy shortages in the near future. Thus, technical advancements in bioelectricity production from wastewater are becoming commercially viable. Due to practical limitations, and although promising prospects have been reported in recent investigations, MFCs are incapable of upscaling and of high-energy production. In this review paper, intensive research has been conducted on MFCs’ applications in the treatment of wastewater. Several types of waste have been extensively studied, including municipal or domestic waste, industrial waste, brewery wastewater, and urine waste. Furthermore, the applications of MFCs in the removal of nutrients (nitrogen and sulphates) and precious metals from wastewater were also intensively reviewed. As a result, the efficacy of various MFCs in achieving sustainable power generation from wastewater has been critically addressed in this study.

Mesilla/Conejos-Médanos Basin: U.S.-Mexico Transboundary Water Resources

Synthesizing binational data to characterize shared water resources is critical to informing binational management. This work uses binational hydrogeology and water resource data in the Mesilla/Conejos-Médanos Basin (Basin) to describe the hydrologic conceptual model and identify potential research that could help inform sustainable management. The Basin aquifer is primarily composed of continuous basin-fill Santa Fe Group sediments, allowing for transboundary throughflow. Groundwater flow, however, may be partially or fully restricted by intrabasin uplifts and limited recharge. The shallow groundwater in the Rio Grande alluvium receives recharge from the Rio Grande and responds to changes in water supply and demand. About 11% of Rio Grande alluvial groundwater volume is recharged annually, an amount that is less than recent withdrawals. Potentially recoverable fresh to slightly brackish groundwater was estimated at 82,600 cubic hectometers in the U.S. portion of the Basin and 69,100 cubic hectometers in the Mexican portion. Alluvial groundwater geochemistry is governed by the evaporative concentration of the Rio Grande and agricultural diversions, whereas deeper groundwater geochemistry is governed by mixing and geochemical processes. Continued refinements to storage estimates, the water budget, and deep groundwater extent and geochemistry can improve estimates of sustainable use and inform alternative water sources.