Optimum Nutrient Concentrations Research Articles

Leaf nutrient-based processes of conservatism and convergence regulate the vertical stratification of plant growth forms during subtropical forest degradation

Unveiling the ecological and evolutionary mechanisms that guide the differentiation of various plant growth forms into vertical forest strata during forest degradation continues to pose a challenge. We utilized the biogeochemical niche theory to decipher these mechanisms. We measured leaf concentrations of basal elements (C, N, P, K, Ca, and Mg) and used them to generate the biogeochemical niches in herbs, shrubs, trees, and climbers from different vertical strata within a degraded forest and its neighboring mature forest in subtropical montane zones. Our results showed that biogeochemical niches varied significantly among growth forms. Biogeochemical niches also differed significantly between species in the degraded and mature forests, as evidenced by the significantly lower leaf C concentration relative to other nutrients in degraded forest species. This could be attributable mainly to the expansive canopy openness in the degraded forest, facilitating the colonization of light-demanding self-supporters and climbers. The phylogenetic signals in leaf nutrient concentrations were significantly present across all species, suggesting the general similarities in biogeochemical niches among closely related species. Following evolutionary model comparisons, stabilizing selection towards varying optimal leaf nutrient concentrations for distinct growth forms in the degraded or mature forest emerged as the most suitable model. Our study thus highlights the important role of phylogenetic biogeochemical niche conservatism and stabilizing selection towards various optimal leaf nutrient compositions for diverse growth forms in both degraded and mature forests in the formation of vertical plant communities during subtropical forest degradation.

Use of a mixture design to optimize dietary macronutrients for large turbot (Scophthalmus maximus Linnaeus, 1758)

Aim of study: Studies on the dietary needs of turbot fish (Scophthalmus maximus Linnaeus, 1758) have largely focused on the juvenile stage; however, there are not many on the larger (300–500 g) species. The purpose of this experiment was to determine the ideal dietary levels of protein, fat, and carbohydrate for large turbot. Area of study: Demre, Antalya, Türkiye. Material and methods: A three-component mixture design model was created to adjust the quantities of dietary protein between 45.6% and 63.4%, carbohydrates between 4.9% and 30.5%, and fat between 5.6% and 17.7%. The components of the model were fish meal (FM), fish oil (FO), and wheat flour (W). Fish initially weighing 301.6±0.1 g on average were fed 14 different diets for 10 weeks. The ideal dietary macronutrient levels were estimated by examining the prediction profiler at the highest desirability based on the variables that were selected to maximize final weight, daily growth coefficient, protein efficiency ratio, nitrogen and energy retentions, and minimize feed conversion ratio, nitrogen and carbon losses. Main results: The optimal diet formulation yielded the highest desirability of 0.87 for all selected responses and resulted in dietary inclusion levels of FM, W and FO as 63.6%, 20.8%, and 9.4%, respectively. The proposed optimal nutrient concentrations for large turbot (growing from 300 to 500 g) are 54% protein, approximately 17% lipid, and 15.8% carbohydrate on dry matter basis. Research highlights: The mixture design successfully allowed us to estimate the optimum levels of dietary protein, lipid and carbohydrate for large turbot.

Optimization of culture medium to improve bio-cementation effect based on response surface method

The main challenge in the large-scale application of MICP lies in its low efficiency and promoting biofilm growth can effectively address this problem. In the present study, a prediction model was proposed using the response surface method. With the prediction model, optimum concentrations of nutrients in the medium can be obtained. Moreover, the optimized medium was compared with other media via bio-cementation tests. The results show that this prediction model was accurate and effective, and the predicted results were close to the measured results. By using the prediction model, the optimized culture media was determined (20.0 g/l yeast extract, 10.0 g/l polypeptone, 5.0 g/l ammonium sulfate, and 10.0 g/l NaCl). Furthermore, the optimized medium significantly promoted the growth of biofilm compared to other media. In the medium, the effect of polypeptone on biofilm growth was smaller than the effect of yeast extract and increasing the concentration of polypeptone was not beneficial in promoting biofilm growth. In addition, the sand column solidified with the optimized medium had the highest strength and the largest calcium carbonate contents. The prediction model represents a platform technology that leverages culture medium to impart novel sensing, adjustive, and responsive multifunctionality to structural materials in the civil engineering and material engineering fields.

Optimization of macronutrient and micronutrient concentrations in roots and leaves for Florida HLB-affected sweet orange trees

Florida sweet orange production has declined largely due to Huanglongbing (HLB) disease. The causative agent, Candidatus Liberibacter asiaticus (CLas) bacteria, lowers tree performance by reducing water and nutrient uptake. HLB-affected trees have a fibrous root density loss of about 30 to 50%, which increases as HLB symptoms develop in the canopy. Currently, no guidelines exist for optimal nutrient concentrations in citrus roots. This study aimed to develop root nutrient and fertilization guidelines for HLB-affected sweet orange trees. The research was conducted on two sites with 5- to 6-year-old ‘Valencia’ sweet orange trees grafted on ‘Swingle’ rootstock. The two sites were representative of the different soil characteristics of the state of Florida, namely Ridge and Flatwood regions. Seven treatments were tested using a randomized complete block design. The Ridge soils site has a high density of trees of about 1359 trees ha−1 while the Flatwoods soils site of southwest Florida has a lower tree density of about 716 trees ha−1. The experiment began in May 2019 and concluded in May 2021. Foliar, root and soil samples were collected from both sites twice a year and nutrient concentrations were analyzed. No significant patterns were observed; however, differences in soil nutrients were found between sites. The obtained data represent trends that could become significant over a longer-term study which encompasses the two different citrus-growing regions in Florida. These lengthier trials are especially needed in the age of HLB in order to curb the declining citrus production.

Determination of optimal soil pH and nutrient concentrations for cultivated rooibos tea using the boundary line approach

Optimal soil pH and nutrient conditions for rooibos cultivation in South Africa have not yet been established as limited field research has been conducted. Soil chemical (0–300 mm) and yield data were collected from 120 commercial rooibos plantations in the main (170 km wide) production region in the Western and Northern Cape Provinces. The optimum and 90%-yield sufficiency soil ranges were determined using the boundary line approach and quadratic regression. The optimum (sufficiency range) soil chemical properties were a pH (KCl) of 4.5 (4.2–4.7), electrical conductivity of 0.23 mS m−1 (0.16–0.30 mS m−1) and acid saturation of 27.5% (17.1–37.8%). The optimum (sufficiency range) soil available macro- and micronutrients (in mg kg−1) were: 16.9 (7.4–26.4) for P, 20.8 (11.5–30.0) for K, 140.3 (95.9–184.7) for Ca, 50.0 (32.3–63.7) for Mg, 8.3 (4.9–11.7) for S, 34.6 (17.2–52.1) for Fe, 5.5 (2.2–8.8) for Mn, 0.30 (0.16–0.45) for Zn, 0.11 (0.07–0.15) for Cu and 0.11 (0.06–0.16) for B. The resultant optimal values for soil pH and available P, K and Mg corresponded with previous published reports on cultivated fynbos species, while published values were not available for the other parameters. The findings of this study are important for sustainable soil fertility management in commercial rooibos tea production in South Africa.

Establishing Critical Leaf Nutrient Concentrations and Identification of Yield Limiting Nutrients for Precise Nutrient Prescriptions of Oil Palm (Elaeis guineensis Jacq) Plantations

African oil palm (Elaeis guineensis Jacq.) is a bulk feeder of nutrients. In this study, we aimed at devising strategies for efficient nutrient management in the oil palm plantations of the Krishna River basin located in Andhra Pradesh, India by assessing soil fertility status, establishing optimal leaf nutrient concentrations and identifying yield restrictive nutrients. In total, 67 oil palm plantations were surveyed from this area in 2020, soil samples were collected and analysed for different soil properties, including pH, EC, SOC, available P, K, S, exchangeable Ca and Mg, and hot water-soluble boron (HWB) in surface (from 0–20 cm depth), subsurface (from 20–40 cm depth) and deep (from 40–60 cm depth) soil layers. As per DRIS (Diagnosis and Recommendation Integrated System) indices estimated in this study, the order of requirement of nutrients is Nitrogen (N) > B > K > P > Mg for this area. Optimum leaf nutrient concentrations ranged between 2.07–4.29%, 0.13–0.27%, 0.52–0.94%, 0.44–0.76% and 44.97–102.70 mg/kg for N, P, K, Mg and B, respectively. In surveyed plantations, about 15, 6, 16, 9 and 12 percent of leaf samples had less than optimum concentration of N, P, K, Mg and B respectively. Nitrogen and Boron are the major yield limiting factors in this region. Leaf nutrient concentrations need to be maintained at the optimum ranges as estimated above for higher productivity in the Krishna basin area.

Natural variations and dynamics of macronutrients for 87 tea plant (Camellia sinensis) varieties throughout the growing seasons in Wuhan

The tea plant (Camellia sinensis (L.) O. Kuntze) is the most extensively consumed beverage crop in the world, with steadily increasing consumption over the last decade. Tea plantations are frequently over-fertilized to achieve enhanced growth and yield, which ultimately influences the soil acidification and compaction, resulting in low quality and yield. However, the effect of optimum nutrient concentrations in the leaves on tea yield and quality is poorly understood. In this study, the dynamics of macronutrients nitrogen (N), phosphorus (P) and potassium (K) levels, nutrient use and remobilization efficiencies, and nutrient requirements (NR) were quantified among the diverse tea plant varieties over the entire growing seasons. Leaf samples of two categories, young leaves and mature canopy leaves, were collected from 87 elite tea varieties during the growing seasons to illustrate their biological significance. The results revealed that the highest average N levels were observed in the 2nd spring tea, P levels in summer tea, and K levels in autumn tea in both young and mature leaves. The results further revealed that a higher average nutrient utilization efficiency for nitrogen (NUtE-N) was identified in the summer followed by autumn. The NUtE-P in autumn and the NUtE-K in the 1st spring tea were relatively higher. Nutrient remobilization efficiencies (NRE) (NRE < 0 and NRE > 0) for N, P and K within canopy leaves were calculated, indicating the alternative roles of sources and sinks during the growth period. Moreover, NRE < 0 was almost exclusively found in the spring and summer, whereas NRE > 0 was mainly observed in the autumn. In terms of requirements, N was the most required for optimal tea yield, followed by K, and then P. Seasonally, maximum N, P and K requirements were coincidentally observed in the 2nd spring tea, whereas the minimum were in summer tea, autumn tea and the 1st spring tea, respectively. Based on nutrient utilization, the nutrient requirements of tea plants and the understanding of natural variability in N, P and K dynamics were elucidated to address agronomic, economic and environmental issues.

Principles of Nutrient and Water Management for Indoor Agriculture

Mass balance principles are a cornerstone of efficient fertilizer use and can be utilized to optimize plant nutrition without discarding or leaching solution. Here, we describe the maintenance of closed hydroponic and soilless substrate systems based on mass balance. Water removed by transpiration is restored with solution that replaces the nutrients that were taken up with the water. The concentration of nutrients in this refill/irrigation solution is determined by multiplying the optimal concentration of each nutrient in plant tissue by the water-use efficiency (WUE; ratio of dry mass to water transpired). Optimal leaf nutrient concentrations are well established, but WUE in controlled environments varies widely and is less well characterized. Elevated CO2 increases photosynthesis and demand for nutrients, but partially closes stomata and reduces transpiration; so high CO2 dramatically increases WUE. The concentration of the refill/irrigation solution must be adjusted to account for a two-fold range of WUE, from 3 g L−1 in ambient CO2 in lower humidity, to 6 g L−1 in elevated CO2 in higher humidity. WUE and nutrient requirements vary during the vegetative and reproductive stages of growth, and adjustment of the solution over the lifecycle can be beneficial. Measurement of solution electrical conductivity (EC) is helpful, but if the solution is appropriate, low EC usually means healthy plants and active nutrient uptake. The ammonium to nitrate ratio is critical to pH management. We have applied these principles across multiple species and environments to achieve long-term, steady-state nutrient concentrations with no discharge or leaching of solution.

Establishment of nutrient sufficiency ranges in olive using boundary-line approach

The establishment of optimum nutrient concentrations provides excellent knowledge for the diagnosis and correction of plant nutritional status to maximize yield. This study was conducted to determine the optimum values and sufficiency ranges of nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), iron (Fe), manganese (Mn), zinc (Zn), and copper (Cu) in olive trees grown in various land forms in Egypt by boundary-line approach. Over two consecutive years, foliar samples from 266 olive trees were collected from different growing areas in Egypt and fruit yields per tree were reported. The derived optimum concentrations for these nutrients by solving the first derivation of the inferred second-degree polynomial functions of the relationship between fruit yield and leaf nutrient concentrations were 1.54% for N, 0.19% for P, 0.87% for K, 1.48% for Ca, 0.22% for Mg, 125 ppm for Fe, 33.7 ppm for Mn, 23.5 ppm for Zn, and 8.6 ppm for Cu. Sufficiency ranges corresponding to 90% of the maximum fruit yield were 1.29%–1.80%, 0.14%–0.24%, 0.66%–1.08%, 1.09%–1.90%, 0.10%–0.33%, 63–165 ppm, 30.2–35.9 ppm, 16.6–30.2 ppm, and 2.8–13.9 ppm, respectively. Since standards of optimum nutrition are not readily available in Egypt and in similar places, the current study provides an important guideline for diagnosing olive trees nutritional status.

Bacterial community dynamics during MEOR biostimulation of an oil reservoir in sumatera Indonesia

Biostimulation is a method of microbial enhanced oil recovery (MEOR) by injecting nutrients into an oil well to stimulate the growth of indigenous bacteria and their activities dealing with the increasing of oil recovery. This study aimed to obtain an optimum nutrient formulation at laboratory scale to be applied for MEOR field biostimulation pilot project. Field monitoring of chemical and bacterial composition in oil well was also carried out up to twelve weeks after biostimulation. The oil composition was analyzed by GC-MS and column chromatography. Bacterial community analysis was performed using 16S rRNA gene as the biomarker, which was sequenced by Illumina Miseq Sequencing. Based on Response Surface Methodology (RSM), the optimum nutrient concentrations that increase bacterial growth and decrease oil viscosity were molasses 5% (w/v), NPK 0.5% (w/v), and DAP 0.5% (w/v). The relative abundance of the bacteria and the community composition constantly changed during the monitoring process. Injection of molasses stimulated the growth of the hydrocarbonoclastic bacteria until the end of monitoring period. • Higher nutrient concentrations does not always stimulate the indigenous bacteria. • During the MEOR monitoring process, saturated and resinic fractions increased. • SRB growth was successfully suppressed by biostimulation treatment. • Biostimulation rise the bacterial community to a significantly different and more diverse species.

Insights into the potential impact of algae-mediated wastewater beneficiation for the circular bioeconomy: A global perspective

Algae-based technologies are one of the emerging solutions to societal issues such as accessibility to clean water and carbon-neutral energy and are a contender for the circular bioeconomy. In this review, recent developments in the use of different algal species for nutrient recovery and biomass production in wastewater, challenges, and future perspectives have been addressed. The ratio and bioavailability of nutrients in wastewater are vital parameters, which significantly impact nutrient recovery efficiency and algal biomass production. However, the optimum nutrient concentration and ratio may vary depending upon the microalgal species as well as cultivation conditions. The use of indigenous algae and algae-based consortia with other microorganisms has been proved promising in improving nutrient recovery efficiency and biomass production in pilot scale operations. However, environmental and cultivation conditions also play a significant role in determining the feasibility of the process. This review further focused on the assessment of the potential benefits of algal biomass production, renewable biofuel generation, and CO2 sequestration using wastewater in different countries on the basis of available data on wastewater generation and estimated nutrient contents. It was estimated that 5–10% replacement of fossil crude requirement with algal biofuels would require ~952–1903 billion m3 of water, 10–21 billion tons of nitrogen, and 2–4 billion tons of phosphorus fertilizers. In this context, coupling wastewater treatment and algal biomass production seem to be the most sustainable option with potential global benefits of polishing wastewater through nutrients recycling and carbon dioxide sequestration.

Optimization of the nutrient growing solution and inoculation rate for Azolla mexicana production and use as fertilizer

Azolla is a water fern that can be utilized and developed as a soil amendment or fertilizer. Azolla hosts Anabaena cyanobacteria in its vacuoles and benefits from atmospheric N fixation by the Anabaena. The purpose of this study was to enhance Azolla production in natural or artificial ponds for field application. We identified the optimum nutrient concentrations and inoculation rate to maximize growth of Azolla mexicana and measured the nutrient concentrations in A. mexicana for use as fertilizer. A. mexicana was cultivated in nutrient solutions in a greenhouse, and ten individual nutrients were examined at four different concentrations using a randomized complete block design with three replicates. In addition, studies on inoculation rate and combined nutrient solutions were conducted. Azolla growth parameters (biomass, relative growth rate (RGR), doubling time, and percent greenness) and nutrient concentrations were measured. There were no significant differences in Azolla growth parameters among nutrient concentrations with all other nutrients held constant, except for Zn which affected the percent greenness. Inoculation rates of 50 to 100 g m−2 were optimum for 14-day Azolla growing periods in the greenhouse. Azolla nutrient concentrations were influenced by nutrient concentrations in the media. A nutrient solution (Widiastuti2) was developed that resulted in excellent Azolla growth, while also being economical due to its lower nutrient concentrations. If, however, higher Azolla micronutrient concentrations are desired, Widiastuti3 or the original Watanabe solution may also be used.

Effects of some factors on carotenoid biosynthesis by Rhodotorula Muclaginosa

Carotenoid compounds are the popular natural antioxidants which are often isolated from plants. There have been more and more researches on carotenoid biosynthesis towards lowering product prices. In this study, in order to produce carotenoid, Rhodotorula mucilaginosa was grown on aqueous media composed of carbon source (glucose, glycerol), nitrogen source (yeast extract, (NH4)2SO4). The optimum nutrient concentration was 10g/L glucose, 10g/L glycerol, the ratio of yeast extract and (NH4)2SO4 (3:7). The fermentation time for obtaining the highest carotenoid yield was 10 days in our research condition. Additionally, some oxidative stress environment for Rhodotorula mucilaginosa was be studied. The result has shown that the low level of Cu2+ (4.5mM) or 1% H2O2 solution (% v/v) in the fermentation media could increase the carotenoid biosynthesis.

Kinetic growth and biochemical composition variability of Chlorella pyrenoidosa in olive oil washing wastewater cultures enriched with urban wastewater

Olive mills generates wastewaters (OMWs) characterized by high organic and inorganic load, which includes sugars, phenolic compounds, polyalcohols, pectins, lipids, Na, K, Ca ..., but deficient in nitrogen and phosphorus. Urban wastewater treatment plants with primary (natural sedimentation) and secondary (biological removal) treatments are unable to remove the total nitrogen and phosphorus from these wastewaters, which can be therefore considered as a sustainable source of both nutrients. The enrichment of OMW with urban wastewater from secondary treatment (UW) can provide optimal nutrient concentrations to produce an algal biomass with high added value. Chlorella pyrenoidosa is a green unicellular alga that can eliminate nutrients and produce biomass with high lipids content. Experiments have been carried out in photobioreactors of 0.5 L useful capacity. Different enriched dilutions of olive oil washing wastewater (OOWW) with ultrapure water (%OOWWenriched = 5–100% v/v) were prepared as culture media. Common operating conditions were pH 8, aeration level 1 v/v/min, initial illumination intensity 126.2 μE/(m2 s) under 12 h light/12 h dark cycles and temperature of 25 °C. Results obtained showed that the highest values of maximum specific growth rate and volumetric biomass productivity were μm = 0.0203 h−1 and Pb = 1.73 × 10-3 g/(L h), respectively. Maximum percentages of chlorophylls (0.96 %) and carotenoids (0.24 %) were obtained in the final biomass of the culture formed by 30 % (v/v) of OOWWenriched. The highest proteins (43.7 %) and lipids (51.5 %) contents were obtained in the biomass from the culture medium with 100 % (v/v) of OOWWenriched, which is suitable for biofuel production. Final treated water could be discharged into water public channels, used in irrigation or as drinking water if other operation units such as ultrafiltration and reverse osmosis are added to the bioprocess.

Spatial regulation of resource allocation in response to nutritional availability

It is critical for a living organism to appropriately allocate resources among its organs, or within a specific organ, because available resources are generally limited. For example, in response to the nutritional environment of their soil, plants regulate resource allocation in their roots in order to plastically change their root system architecture (RSA) for efficiently absorbing nutrients. However, it is still not understood why and how RSA is adaptively controlled. Therefore, we modeled and investigated the spatial regulation of resource allocation, focusing on RSA in response to nutrient availability, and provided analytical solutions to the optimal strategy in the case of simple fitness functions. We first showed that our model could explain the experimental evidence where root growth is maximized at the optimal nutrient concentration under the homogeneous condition. Next, we extended our model to incorporate the spatial heterogeneity of nutrient availability. This extended model revealed that growth suppression by systemic control is required for adapting to high nutrient conditions, whereas growth promotion by local control is sufficient for adaptation to low-nutrient environments. This evidence predicts that systemic control can be evolved in the presence of excessive amounts of nutrition, consistent with the ‘N-supply’ systemic signal that is observed experimentally. Furthermore, our model can also explain various experimental results using nitrogen nutrition. Our model provides a theoretical basis for understanding the spatial regulation of adaptive resource allocation in response to nutritional environment.

Improvement of Bioethanol Production from Sweet Sorghum Juice under Very High Gravity Fermentation: Effect of Nitrogen, Osmoprotectant, and Aeration

To improve ethanol production fermentation efficiency from sweet sorghum juice under a very high gravity (VHG, 280 g/L of total sugar) condition by Saccharomyces cerevisiae NP01, dried spent yeast (DSY), yeast extract, and glycine concentrations were optimized using an L9 (34) orthogonal array design. The results showed that the order of influence on the ethanol concentration (PE) was yeast extract &gt; glycine &gt; DSY. The optimal nutrient concentrations for ethanol production were determined as follows: yeast extract, 3; DSY, 4; and glycine, 5 g/L. When a verification experiment under the projected optimal conditions was done, the P, ethanol yield (Yp/s), and ethanol productivity (Qp) values were 120.1 g/L, 0.47, and 2.50 g/L·h, respectively. These values were similar to those of the positive control experiment with yeast extract supplementation at 9 g/L. The yeast viability under the optimal condition was higher than that of the control experiment. To improve sugar utilization and ethanol production, aeration at 2.5 vvm for 4 h was applied under the optimal nutrient supplementation. The P, Yp/s, and Qp values were significantly increased to 134.3 g/L, 0.50, and 2.80 g/L·h, respectively.

Mutational loss of carotenoids in alkaliphilic Bacillus pseudofirmus OF4 results in sensitivity to oxidative stress and growth at high pH.

Alkaliphilic Bacillus pseudofirmus OF4, which has a broad pH growth range of 7.5 to above 10.5, is yellow-pigmented due to carotenoids. Carotenoids contribute to membrane rigidity and can alleviate cellular oxidative stress. This study was undertaken to gain insight into the roles carotenoids play in alkaliphile physiology. Carotenoid content was high in stationary phase and in cells grown nonfermentatively at pH 10.5 A colourless mutant was isolated by the in-frame deletion of a key carotenogenic gene, crtM. In cells grown to stationary phase in a pH 10.5 medium with a suboptimal concentration of Na+, the ∆crtM strain exhibited lower resistance to paraquat and hydrogen peroxide. Preincubation of the mutant in a nutrient-free pH 10.5 buffer revealed a pronounced sensitivity to hydrogen peroxide in growth at pH 7.5. In growth curves in media with optimal or suboptimal nutrient concentrations conducted at 37°, the mutant grew identically to the wild-type at pH 7.5 but its lag time was longer than the wild-type at pH 10.5 and growth was slower when the carbon source, malate, was limiting. When the temperature of the growth curves was lowered to 25°, the mutant no longer had a pH 10.5 phenotype, implicating the effect of carotenoids on membrane rigidity for the pH 10.5 growth phenotype. These results suggest that carotenoids in B. pseudofirmus OF4 play a role in managing oxidative stress when cells are adapting to other stressful conditions such as nutrient limitation while also helping to maintain membrane fluidity/rigidity balance for membrane-linked functions.

Concomitant production of fatty acid methyl ester (biodiesel) and exopolysaccharides using efficient harvesting technology in flat panel photobioreactor with special sparging system via Scenedesmus abundans

Current study focusses on the concomitant production of fatty acid methyl ester (FAME, biodiesel) and exopolysaccharides (EPS) from Scenedesmus abundans cell factory in flat panel photobioreactor using cost effective harvesting strategy. Parallel mini and medium scale flat panel photobioreactors (PBRs) with special gas sparging system enabling high gas to liquid mass transfer and efficient mixing were designed. Biomass titer of 6.9 g/l with overall biomass productivity of 1.2 g/l/day was achieved with constant high light intensity of 2162 µE/m2/s in growth phase (134 h) using optimum nutrient concentration. FAME concentration of 1.53 g/l was achieved after 15 days of nitrogen deprivation condition with productivity of 67 mg/l/day. The EPS production of 236 mg/l with a yield of 37 mg/g biomass was achieved. The strain proved its capability to produce multiproducts simultaneously in a single stage PBR by natural autoflocculation harvesting technology.

Culture of lily (Lilium sp.) ‘Table Dance’ in an aquaponic system

Aquaponics could be a sustainable crop production system to reduce the excess of fertilizers and pesticides that end up polluting the environment. This study was conducted in order to determine the effect of aquaponics nutritional treatments in growth and development of oriental Lilium sp. 'Table Dance'. Three aquaponics treatments were established: 1) aquaponics, 2) aquaponics + N, K, Ca and S in nutrient solution, and 3) aquaponics + foliar fertilization (FF). A hydroponics treatment (50% Steiner nutrient solution) was used as a control. Plant height, stem diameter, number of leaves, leaf area, fresh and dry weight, number of flowers and vase life were measured in plants, as well as pH, electrical conductivity, nutrient concentration in aquaponic nutrient solution and nutrient content in plant tissue. Length, width and weight of fish also were measured. Aquaponics + FF had negative effects on leaves and flowers and on plant quality. Aquaponics + N, K, Ca and S generated optimum nutrient concentrations in solution and in plant tissue, as well as optimum growth and development (leaf area, dry weight, fresh weight, number of flowers and vase life) of lilies, yielding a good standard for quality of flowers.

Two-Phase Flow Modeling of Solid Dissolution in Liquid for Nutrient Mixing Improvement in Algal Raceway Ponds

Achieving optimal nutrient concentrations is essential to increasing the biomass productivity of algal raceway ponds. Nutrient mixing or distribution in raceway ponds is significantly affected by hydrodynamic and geometric properties. The nutrient mixing in algal raceway ponds under the influence of hydrodynamic and geometric properties of ponds is yet to be explored. Such a study is required to ensure optimal nutrient concentrations in algal raceway ponds. A novel computational fluid dynamics (CFD) model based on the Euler–Euler numerical scheme was developed to investigate nutrient mixing in raceway ponds under the effects of hydrodynamic and geometric properties. Nutrient mixing was investigated by estimating the dissolution of nutrients in raceway pond water. Experimental and CFD results were compared and verified using solid–liquid mass transfer coefficient and nutrient concentrations. Solid–liquid mass transfer coefficient, solid holdup, and nutrient concentrations in algal pond were estimated with the effects of pond aspect ratios, water depths, paddle wheel speeds, and particle sizes of nutrients. From the results, it was found that the proposed CFD model effectively simulated nutrient mixing in raceway ponds. Nutrient mixing increased in narrow and shallow raceway ponds due to effective solid–liquid mass transfer. High paddle wheel speeds increased the dissolution rate of nutrients in raceway ponds.