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researchers hypothesized that the bees' heat tolerance would increase with body size; that male heat tolerance would increase with ambient temperatures above ground whereas female heat tolerance would increase with sandier soils; and that parasite infection would reduce heat tolerance

trimmed at 7 cm and irrigated two times a week to field capacity.

Six weeks after transplanting

For drought stress treatment, the amount of irrigation water was determined based on evapotranspiration (ET) loss by weighing the pots every other day and the irrigation was provided to compensate 30% to 50% ET loss. ET was determined by weighing the pots.

VWC was reduced from 34.6% to 27.9% between day 0 and day 7, from 27.9% to 23.4% between day 7 and day 14, from 23.4%% to 14.5% between day 14 to day 21, and from 14.5% to 5.1% between day 21 and day 28.

Leaf chlorophyll was extracted with acetone and measured using a spectrophotometer

Leaf photosynthetic rate and stomatal conductance were measured using a portable photosynthetic system

turf quality started to decline at day 7 due to drought stress.

Drought stress reduced turf quality rating by 14.8% relative to the control at the end of drought stress (28 d).

The electrolyte leakage increased gradually from day 7 through day 21 due to drought stress.

Drought stress increased electrolyte leakage by 35.6% at day 14, 95.7% at day 21, and 105.4% at day 28 when compared to the control.

chlorophyll began to decline after day 7 due to drought stress

educed chlorophyll content by 39.0% relative to the control.

photosynthetic rate due to drought stress was observed as early as day 7

Stomatal conductance decline was first observed at day 4 of drought stress

day 28 when drought stress reduced stomatal conductance by 84.4%

The ZR level declined gradually from day 14 through day 28 due to drought stress. Drought stress reduced ZR by 28.5% at day 14, 35.1% at day 21, and 59.1% at day 28 relative to the control.

1 week after ZR did. At the end of drought stress (day 28), drought stress reduced iPA by 50.4% relative to the control.

Drought stress reduced leaf IAA by 14.3% and 26.7% at day 21 and day 28, respectively, when compared to the control.

The ABA started to accumulate after day 4 of drought stress and the difference between drought stress and the control was observed as early as 7 d of drought stress

The ABA content gradually increased from day 7 through day 28. Drought stress increased leaf ABA by 23.6% at day 7, 30.7% at day 14, 87.6% at day 21, and 108.5% at day 28 relative to the control.

drought stress did not impact leaf GA4 content

We found that ABA/CK increased sharply from day 14 through day 28 due to increase in ABA and decline in CK (ZR + iPA) during the same period. At the end of trial (day 28), drought stress induced an increase in leaf ABA/CK ratio by 3.4-fold relative to the control.

The uncomplicated cellular structures and rapid growth of microalgae endow them with CO2 fixation efficiency as higher as 10–50 folds than terrestrial plants

Recently, many research studies have come up showing the positive impact of growing microalgae under high concentrations of Ci in the form of pure gaseous CO2, real or simulated flue gas, or soluble carbonate (bicarbonate), reporting increased carbon bio-fixation and biomass productivity

Despite such remarkable potential, the production of microalgae for low-value bulk products, such as proteins for food/feed applications, fatty acids for nutraceuticals or bulk products such as biofuels, is heretofore, not economically feasible

The microalgal biomass majorly constituted of lipids (7–23%), proteins (6–71%) and carbohydrates (5–64%), depending upon the microalgal specie and culture conditions

Biofuels from microalgae, production system, conversion technologies, life cycle analyses have been extensively reviewed, hence detailed description is not presented in this review.

the lipid content of common microalgae such as Chlorella, Dunaliella, Isochrysis, Nannochloris, Nannochloropsis, Neochloris, Phaeodactylum, Porphyridium, and Schizochytrium, varies between 20 and 50% of cell dry weight

can be augmented to higher levels by manipulating environmental and other growth factors, process optimization and genetic modifications of the production strain. Nitrogen starvation and salinity stress are known to induce an increase in TAG (triacylglycerol) accumulation and relative content of oleic acid in most of the microalgal species

C14:0, C16:0, C18:1, C18:2, and C18:3 fatty acids, yet the relative composition varies from species to species

The lipids can be converted into FAMEs (fatty acid methyl esters) via transesterification for biodiesel production.

The resistance of cell wall to enzyme hydrolysis is one of the prime bottleneck in the Anaerobic digestion (AD) process. The overall economic feasibility of the process depends on the factors affecting AD, microalgal strain, biomass pretreatment, and culture methods (Jankowska et al., 2017). Lately, to make the system economically viable and environmentally sustainable, a closed-loop production scheme is being adopted wherein AD effluents are recycled and used as an input in the first step of AD. Jankowska et al. (2017) have presented a detailed review microalgae’s cultivation, harvesting and pretreatment for AD for biogas production.

Bioethanol The carbohydrate part (mainly glucose, starch, cellulose, and hemicellulose) of the microalgal dry biomass can be used for transforming into bioethanol via fermentation. Although, microalgae accumulate relatively low quantities of sugars, the absence of lignin from microalgal structure makes them advantageous over other feedstock such as corn, sugarcane, and lignocellulosic biomass (Odjadjare et al., 2015; Jambo et al., 2016). Isochrysis galbana, Porphyridium cruentum, Spirogyra sp., Nannochloropsis oculate, Chlorella sp., are mainly exploited microalgae for the production of carbohydrates

Despite having notable significance, limited number of studies have reported laboratory stage work on the fermentation of microalgae biomass to butanol (Cheng et al., 2015; Gao et al., 2016; Wang et al., 2016).

Value-Added Products In the context of biorefinery approach, intracellular compounds and metabolites have gained immense importance owing to their high monetary value. Microalgal pigments: chlorophyll a and b, lutein, astaxanthin, β-carotene, phycobilins, C- phycocyanin have found wide application in dyes, cosmetics, food and feed additives, nutraceuticals and pharmaceuticals, as natural colors, bioactive components, anti-oxidants, nutritive and neuro-protective agents (Koller et al., 2014; Begum et al., 2016). Microalgae are also exploited as rich source of amino acids (leucine, asparagine, glutamine, cysteine, arginine, aspartate, alanine, glycine, lysine, and valine), Carbohydrates (β1–3- glucan, amylose, starch, cellulose, and alginates), Vitamins and minerals (vitamin B1, B2, B6, B12, C, and E; biotin, folic acid, magnesium, calcium, phosphate, iodine) that are widely used in Food additives, health supplements and medicine. Microalgae, such as Nannochloropsis, Tetraselmis, and Isochrysis are used for extraction of long chain fatty acids popularly known as the omega fatty acids such as DHA (Docosahexaenoic Acid) and EPA (Eicosapentaenoic Acid), have lately gained prime attention as essential for human brain development and health. Other than these, microalgae are also used for production of Extracellular Polymeric Substances (EPSs) which have many industrial applications and Polyhydroxyalkanoates (PHAs). PHAs can be used for manufacturing bioplastics that are very sought after because of their biodegradability (Markou and Nerantzis, 2013; Koller et al., 2014).

Although many have reported successful utilization of microalgal biomass for the production of bioproducts within a biorefinery framework, the economic feasibility is unrealized and the microalgae biorefinery is way much expensive (’t Lam et al., 2017; Zhou et al., 2017). To attain feasibility and sustainability, both upstream processing (USP) and downstream processing (DSP) need to be efficiently simplified and integrated. The efficiency of the USP is determined by microalgal strain selection, nutrient supply (CO2, N, and P) and culture conditions (temperature, light intensity) (Vanthoor-Koopmans et al., 2013). Whereas, the constraints at the DSP level are mainly characterized by harvesting, cell disruption, and extraction methods. DSP, specifically harvesting accounts for 20–40% of the total production costs and for a multi-product biorefinery, the cost increases to 50–60% (’t Lam et al., 2017).

Bioprospecting suitable microalgae is a crucial but time intensive step

mixed diverse community of microalgae, dominated by Desmodesmus spp., could be adapted over a time of many months to survive in 100% flue gas from an unfiltered coal-fired power plant containing 11% CO2

Besides stress manipulation and acclimatization, desirable traits of the microalgal strains can be effectively improved by genetic and metabolic engineering/synthetic biology. Lately, genome editing tools such as Clustered Regularly Interspaced Short Palindromic Repeats – CRISPR associated protein 9 (CRISPR-Cas9) and Transcription Activator-Like (TAL) Effector Nucleases (TALEN) are being used in microalgal gene alterations. Moreover, gene-interfering tools, such as CRISPR-dCas9, micro RNA (miRNA), and silence RNA (siRNA) are being explored to alter the gene expression unlike gene modification.

Flocculation is a low-cost alternative. Cationic chemical flocculants and polymeric flocculants are generally used (Brennan and Owende, 2010), but can negatively affect the toxicity of the biomass and output water (Ryan, 2009). Zhou et al. (2012) reported a novel fungi assisted bioflocculation technique, in which a filamentous fungal spores were added to the algal culture under optimized conditions and the pellets were formed after 2 days that can be harvested by simple filtration. Attached culture can also make harvesting simple (Wang et al., 2017).

. Recent technoeconomic analyses and life-cycle assessments of microalgae-based production systems have suggested that the only possible way for scaling up the production is to completely use the biomass in an integrated biorefinery set-up wherein every valuable component is extracted, processed and valorized.

CCS operate over 3 major steps: CO2 capture, CO2 transportation and CO2 storage.

carbon capture and storage (CCS)

Solanum ptychanthum or black nightshade, and Solanum carolinense, or Carolina horsenettle, also produce toxic berries and are native to Arkansas.

To develop the picture set, a team of psychologists, neuroscientists, and registered dietitians selected foods to represent either minimally processed or ultra-processed foods.

The foods were prepared in a lab, visually represented through professional photography, and controlled for consistency. Researchers also gathered price, food weights, and nutritional information -- calories, macronutrients, sodium, and dietary fiber -- for the food in each image.

researchers recruited 67 nutrition professionals and asked them to classify the foods as minimally or ultra-processed

Story Source: Materials provided by Virginia Tech. Original written by Leigh Anne Kelley. Note: Content may be edited for style and length.

Journal Reference: Zach Hutelin, Monica Ahrens, Mary Elizabeth Baugh, Mary E. Oster, Alexandra L. Hanlon, Alexandra G. DiFeliceantonio. Creation and validation of a NOVA scored picture set to evaluate ultra-processed foods.. Appetite, 2024; 198: 107358 DOI: 10.1016/j.appet.2024.107358