Biomass Production Rate Research Articles

Fertilización de dos grupos genéticos de Pinus patula Schiede ex Schltdl. & Cham. en un ensayo de progenies de cuatro años

Introduction: Genetic improvement and nutritional management are used to increase productive capacity. Objective: To analyze the effect of traditional and controlled-release fertilizers, as well as the way to define the doses (technically or empirically), on growth of 20 tree families of Pinus patulaSchiede ex Schltdl. & Cham. Materials and methods: Four fertilization treatments were applied: 1) control; 2) “technical”, based on foliar analysis; 3) controlled release (18-6-12 + 2CaO + 3.5 Mg + 2.1 Si + microelements); and 4) mixture of agricultural fertilizers in nutrient concentrations similar to the controlled-release treatment. Height, diameter, biomass index, number of whorls, leaf mass, and growth initiation and cessation were evaluated in a group of 10 superior and 10 inferior three-year old families in Chignahuapan, Puebla. Data were analyzed with the MIXED procedure of SAS. Results and discussion: Trees showed no significant differences in growth, biomass production and growth initiation by fertilization effect, but showed significant differences by genetic quality (P ≤ 0.05). The genotype*fertilization interaction was significant; after one year of controlled-release fertilizer application, inferior genotypes had the highest values of relative rates of biomass production, diameter at root collar and height. Conclusions: Controlled-release fertilizers at appropriate doses and environmental conditions are a viable option to promote growth of young P. patula trees in the field.

Drivers of variation in crustacean zooplankton production rates differ across regions off the west coast of Vancouver Island and in the subarctic NE Pacific

Abstract The subarctic NE Pacific is comprised of several oceanographic regimes, in which regional variability in sea surface temperature (SST), satellite chlorophyll a, and crustacean zooplankton biomass influence the production rates of crustacean zooplankton. Traditional methods for estimating zooplankton production rates are labour/time intensive and restricted to select copepod species. A practical field alternative is the ‘chitobiase method’, which yields community-level biomass production rates (BPR) analogous to traditional moulting rate methods. BPR was measured along the west coast of Vancouver Island and in the subarctic NE Pacific during 2005, 2009–2011, and 2015–2018. Generalized additive modelling identified SST and the developing crustacean zooplankton biomass as key drivers of BPR variability. BPR varied positively with the proportion of developing copepod biomass relative to that of non-copepod crustacean zooplankton biomass. Our analysis indicates that BPR variation is associated with zooplankton community composition, but that high zooplankton biomass is not necessarily predictive of high BPR. Specifically, higher BPR is associated with a higher relative biomass of large-bodied, cold-water indicator species, and a lower biomass of non-copepod crustaceans.

Hydrothermal plumes as hotspots for deep-ocean heterotrophic microbial biomass production

Carbon budgets of hydrothermal plumes result from the balance between carbon sinks through plume chemoautotrophic processes and carbon release via microbial respiration. However, the lack of comprehensive analysis of the metabolic processes and biomass production rates hinders an accurate estimate of their contribution to the deep ocean carbon cycle. Here, we use a biogeochemical model to estimate the autotrophic and heterotrophic production rates of microbial communities in hydrothermal plumes and validate it with in situ data. We show how substrate limitation might prevent net chemolithoautotrophic production in hydrothermal plumes. Elevated prokaryotic heterotrophic production rates (up to 0.9 gCm−2y−1) compared to the surrounding seawater could lead to 0.05 GtCy−1 of C-biomass produced through chemoorganotrophy within hydrothermal plumes, similar to the Particulate Organic Carbon (POC) export fluxes reported in the deep ocean. We conclude that hydrothermal plumes must be accounted for as significant deep sources of POC in ocean carbon budgets.

A Two-Step Cultivation Strategy for High Biomass Production and Lipid Accumulation of Raphidocelis subcapitata Immobilized in Alginate Gel

This work focuses on a culture strategy that combines high biomass production and lipid accumulation in the green microalgae Raphidocelis subcapitata immobilized in alginate gel in order to obtain high lipid productivity for biodiesel production. The study of the effects of nitrogen and phosphorus deficiency on lipid accumulation and biomass production in immobilized microalgae showed that both conditions (N− and P−) promoted lipid accumulation in the microalgae. The lipid contents achieved under nitrogen (31.7% ± 3.2% (dcw)) and phosphorus (19.4% ± 1.9% (dcw)) deficiency conditions were higher than those obtained in the complete medium (control) (14.9% ± 1.5% (dcw)). The highest lipid productivity was recorded under nitrogen deficiency conditions (PL = 11.1 ± 1.1 mg/L/day). This indicated that nitrogen deficiency was more effective than phosphorus deficiency in terms of triggering lipid accumulation in the microalgae. However, the conditions for inducing lipid accumulation (N− or P−) resulted in slower growth. In order to address this issue and achieve high lipid productivity, a two-step culture strategy was used. Immobilized R. subcapitata was cultivated under optimal concentrations of nitrogen and phosphorus to achieve a high biomass concentration. Thereafter, the beads containing the microalgae were transferred to a culture medium under nitrogen deficiency conditions in order to induce lipid accumulation. The concentrations 1.5 g/L of NaNO3 and 20 mg/L of K2HPO4 were determined as being the optimal concentrations for growth, and they produced the highest biomass production rates (µm max = 0.233 ± 0.023 day−1 and µm max = 0.225 ± 0.022 day−1 for NaNO3 and K2HPO4, respectively) from all of the concentrations studied. With the two-step culture strategy, immobilized R. subcapitata accumulated 37.9 ± 3.8% of their dry weight in lipid and reached a lipid productivity value of PL = 40.3 ± 4.0 mg/L/day under nitrogen deficiency conditions. This value was approximately 3.6 times higher than that obtained in the direct culture of cells under nitrogen deficiency conditions (PL = 11.1 ± 1.1 mg/L/day).

DECOMPOSITION OF THE REMAINING STRAW DURING SOYBEAN GROWING IN THE MIDWESTERN PARANÁ, BRAZIL

Crop biomass plays an important role, especially in tropical and subtropical crops that adopt the no-tillage system, whose decomposition is related to material composition and environmental conditions. The objective of this work was to analyze the decomposition of straw remaining from autumn/winter crops in the development of soybean in succession in the Midwest region of Paraná. The experiment was conducted between 2019 and 2021 in a completely randomized design, with eight treatments (spontaneous, black oat, brachiaria, corn, wheat, oilseed radish, corn + brachiaria, and black oat + oilseed radish) and four replications. After autumn/winter cultivation, biomass samples were dried and placed in nylon bags, returning to the original plot during soybean sowing. The decomposition bags were collected in seven periods over 120 days, coinciding with the soybean cycle. The decomposition rate was analyzed by regression. The regression equations and the amount of biomass remaining from the autumn/winter seasons were determinate the half-file and the remaining mass on the soil surface at sowing and at 30, 60, 90, and 120 days after sowing. Biomass production and decomposition rate varied with the season, depending on environmental conditions. Wheat had the lowest decomposition rate with a half-life greater than 100 days. Intercropping crops reduce the decomposition rate.

Identification and growth study of potential probiotic isolated from pineapple, watermelon, and banana peels

This study aimed to isolate, identify, and conduct a growth study of potential probiotics from pineapple peel (PP), watermelon peel (WP), and banana peel (BP). Six strains were isolated, and the growth study was conducted at 30°C at 150 rpm after 24 hr incubation. Based on colony characteristics, cell morphology, and gene sequencing, the isolates were identified as yeast strains, namely, Meyerozyma caribbica (PP) and Candida orthopsilosis (WP and BP). M. caribbica showed the highest biomass production of 2.34 g/L. Less biomass production of 2.01 and 2.18 g/L was obtained for C. orthopsilosis (WP and BP), respectively. The maximum specific growth rate in the exponential phase was 1.83 and 1.23 h−1 for C. orthopsilosis (WP and BP), followed by 1.04 hr−1 for M. caribbica, respectively. M. caribbica isolated from PP belongs to the group of potential yeast probiotics which is a good candidate for further studies to determine its probiotic properties. Novelty impact statement Waste utilization for an economical and alternative natural source of probiotic production. The probiotic potential in yeasts has not been extensively studied before. In this study, Meyerozyma caribbica was identified from pineapple peels as a new yeast probiotic starter. M. caribbica exhibited the highest biomass production and maximum growth rate, so these essential parameters in determining the quantitative importance should be considered.

Biomass increment and carbon sequestration in hedgerow-grown trees

The global role of tree-based climate change mitigation is widely recognized; trees sequester large amounts of atmospheric carbon, and woody biomass has an important role in the future biobased economy. In national carbon and biomass budgets, trees growing in hedgerows and tree rows are often allocated the same biomass increment data as forest-grown trees. However, the growing conditions in these linear habitats are different from forests given that the trees receive more solar radiation, potentially benefit from fertilization residuals from adjacent fields and have more physical growing space. Tree biomass increment and carbon storage in linear woody elements should therefore be quantified and correctly accounted for. We examined four different hedgerow systems with combinations of pedunculate oak, black alder and silver birch in northern Belgium. We used X-ray CT scans of pith-to-bark cores of 73 trees to model long-term (tree life span) and short-term (last five years) trends in basal area increment and increment in aboveground stem biomass. The studied hedgerows and tree rows showed high densities (168–985 trees km-1) and basal areas (22.1–44.9 m2 km-1). In all four hedgerow systems, we found a strong and persistent increase in stem biomass and thus carbon accumulation with diameter (long-term trend). The current growth performance (short-term trend) also increased with tree diameter and was not related to hedgerow tree density or basal area, which indicates that competition for light does not (yet) limit tree growth in these ecosystems. The total stem volume was 82.0–339.7 m³ km-1 (corresponding to 18.8–100.7 Mg aboveground carbon km-1) and the stem volume increment was 3.1–14.5 m³ km-1 year-1 (aboveground carbon sequestration 0.7–4.3 Mg km-1 year-1). The high tree densities and the persistent increase in growth of trees growing in hedgerow systems resulted in substantial wood production and carbon sequestration rates at the landscape scale. Our findings show that trees growing in hedgerow systems should be included when biomass and carbon budgets are drafted. The biomass production rates of hedgerow trees we provide can help refine the IPCC Guidelines for National Greenhouse Gas Inventories.

Organic Molecular Paleohypsometry: A New Approach to Quantifying Paleotopography and Paleorelief

Stable isotope paleoaltimetry is one of the most commonly used approaches for quantifying the paleoelevation history of an orogen yet this methodology is often limited to arid to semi-arid climates, mountain systems with a clear orographic rainshadow and terrestrial basins. We present a new approach to reconstructing past topography and relief that uses the catchment-integrated signature of organic molecular biomarkers to quantify the hypsometry of fluvially-exported biomass. Because terrestrially-produced biomolecules are synthesized over the full range of global climate conditions and can be preserved in both terrestrial and marine sediments, the geochemistry of fluvially-transported sedimentary biomarkers can provide a means of interrogating the evolution of topography for a range of environments and depositional settings, including those not well suited for a traditional isotope paleoaltimetry approach. We show an example from Taiwan, a rapidly eroding tropical mountain system that is characterized by high rates of biomass production and short organic residence time and discuss key factors that can influence molecular isotope signal production, transport and integration. Data show that in high relief catchments of Taiwan, river sediments can record integration of biomass produced throughout the catchment. Sedimentary biomarker δ2HnC29 in low elevation river deposition sites is generally offset from the δ2HnC29 value observed in local soils and consistent with an isotope composition of organics produced at the catchment mean elevation. We test the effect of distinct molecular production and erosion functions on the expected δ2HnC29 in river sediments and show that elevation-dependent differences in the production and erosion of biomarkers/sediment may yield only modest differences in the catchment-integrated isotopic signal. Relating fluvial biomarker isotope records to quantitative estimates of organic source elevations in other global orogens will likely pose numerous challenges, with a number of variables that influence molecular production and integration in a river system. We provide a discussion of important parameters that influence molecular biomarker isotope signatures in a mountain system and a framework for employing a molecular paleohypsometry approach to quantifying the evolution of other orogenic systems.

Carbon dioxide delivery and resulting biomass separation in microalgae cultivation using triethanolamine

ABSTRACT This study investigates a novel use of triethanolamine (TEA), a well-known carbon dioxide (CO2) – capturing chemical, to simultaneously deliver CO2 and separate microalgae biomass from the growth media in microalgae cultivation processes. For this purpose, the growth and nutrient utilization rates of Chlorella sp., were monitored at different concentrations of TEA saturated with 15% of CO2 in a gas mixture. In addition, the total inorganic carbon content in the growth media was followed in order to estimate the CO2 delivery rates. The highest growth and nutrient utilization rates occurred at 20 and 30 mM TEA concentrations, which results in 2.5-fold increase in biomass production rate at these TEA concentrations. More than 85% of the produced biomass was successfully separated from the medium by flotation facilitated by the release of oxygen and CO2 gases to the air from the oversaturated growth media, as well as the surfactant characteristics of TEA.

Bio-Mitigation of Carbon Dioxide Using Desmodesmus sp. in the Custom-Designed Pilot-Scale Loop Photobioreactor

Today’s society is faced with many upfront challenges such as the energy crisis, water pollution, air pollution, and global warming. The greenhouse gases (GHGs) responsible for global warming include carbon dioxide (CO2), methane (CH4), nitrous oxide (NOx), water vapor (H2O), and fluorinated gases. A fraction of the increased emissions of CO2 in the atmosphere is due to agricultural and municipal solid waste (MSW) management systems. There is a need for a sustainable solution which can degrade the pollutants and provide a technology-based solution. Hence, the present work deals with the custom design of a loop photobioreactor with 34 L of total volume used to handle different inlet CO2 concentrations (0.03%, 5%, and 10% (v/v)). The obtained values of biomass productivity and CO2 fixation rate include 0.185 ± 0.004 g L−1 d−1 and 0.333 ± 0.004 g L−1 d−1, respectively, at 10% (v/v) CO2 concentration and 0.084 ± 0.003 g L−1 d−1 and 0.155 ± 0.003 g L−1 d−1, respectively, at 5% (v/v) CO2 concentration. The biochemical compositions, such as carbohydrate, proteins, and lipid content, were estimated in the algal biomass produced from CO2 mitigation studies. The maximum carbohydrate, proteins, and lipid content were obtained as 20.7 ± 2.4%, 32.2 ± 2.5%, and 42 ± 1.0%, respectively, at 10% (v/v) CO2 concentration. Chlorophyll (Chl) a and b were determined in algal biomass as an algal physiological response. The results obtained in the present study are compared with the previous studies reported in the literature, which indicated the feasibility of the scale-up of the process for the source reduction of CO2 generated from waste management systems without significant change in productivity. The present work emphasizes the cross-disciplinary approach for the development of bio-mitigation of CO2 in the loop photobioreactor.

Bench scale demonstration of greywater treatment in a 3-stage sequential process comprising anaerobic, aerobic, and vertical greenery system

Non-potable reuse of treated greywater (GW) within households can reduce daily freshwater consumption and provide water security. Urban household in India was estimated to discharge 38–45 L GW/capita·day with an average composition of (mg/L) COD 238.05; total Kjeldahl nitrogen (TKN) 31.08; total phosphorus (TP) 2.85; anionic surfactants (AS) 0.5 and faecal coliform log 6.09 CFU/100 mL, etc. A 100 L/day bench-scale, 3-stage sequential GW treatment process was optimized and its long-term performance was demonstrated with synthetic GW feedstock corresponding to the aforementioned characteristics. The treatment process comprises a multi-chambered upflow anaerobic biofilm reactor (AnBR) followed by an upflow aerobic reactor (AeR) and vertical greenery system (VGS) inhabited by flowering creeper Sphagneticola trilobata. At steady-state HRT of ~2.25 day the process achieved the following pollutant removal (as %) COD 93.23; turbidity (NTU) 98.75; total nitrogen (TN) 54.23; TP 96.42; AS 92.97; faecal coliform: 99.95 when fed with an average influent characteristics of (mg/L) COD 281, TN: 24.41, TP 1.13, AS 16.66, faecal coliform 6 log CFU/100 mL, pH 8.85, NTU 63.3. The predominant removal of COD and AS took place in AnBR and AeR respectively, whereas, VGS demonstrated relatively higher removal of turbidity, TKN, and faecal coliforms. The inefficient nitrification-denitrification in AeR was attributed to a lower influent C/N ratio of 3.18. The acclimatization of VGS to the tertiary treatment process exhibited an aerial biomass production rate of 5063.37 mg TS/m2·d. The treated water attained the standards for household recycling as prescribed by WHO.

Bioreactor for the cultivation of Arthrospira platensis under controlled conditions

A vertical flat-type bioreactor consisting of transparent polyethylene (food safe) was constructed, which is characterized by a flexible design and allows the adjustment of a light path of 1 cm – 8.5 cm and a working volume of 1.5 l – 4 l. To characterize the performance of the bioreactor, cultivation experiments were performed with the cyanobacterium Arthrospira platensis (AP). The growth was assessed continuously by monitoring optical density and intermittently by measuring the dry weight of the AP biomass. An on-line measurement technique for estimating biomass production rate in a photosynthetic microalgae culture was developed. The oxygen produced by AP in the culture medium was flushed out sparging using a mixture of air and CO2 (1%). Factors which might influence the AP growth were monitored: pH, temperature, oxygen concentration and the filling level were corrected automatically to compensate evaporation losses. As an example, the huge influence of the light intensity on the AP growth was tested. The increase of the photon flux density of 15 to 1200μmol/(l · d) led to a 22-fold increase of the productivity and a 3.1-fold shorter doubling time. Using an online measurement technique - together with the control of the growth process via a wireless local area network (WLAN) router and virtual private network - allows monitoring the growth of Arthrospira platensis remotely.

Cultivation of Autochthonous Microalgae for Biomass Feedstock: Growth Curves and Biomass Characterization for Their Use in Biorefinery Products

In this work, the biomass productivity for biorefinery products and growth curves of three autochthonous microalgae collected in different reservoirs (“Scenedesmus sp.” (SSP), mixture of Scenedesmus sp., Chlorella minutissima, Chlorellas sp. and Nannochloropsis sp. named “La Orden” (LO) consortium and Chlorella minutissima named “Charca Brovales” (CB) consortium) were studied in a 5.5 L column laboratory photobioreactor. Two different culture media, Arnon culture (AM) and an agriculture fertilizer-based liquid medium (FM), have been used to evaluate the growth effect of the microalgae; it was found that the medium has a clear effect on the biomass productivity and growth rate, which ranged between 0.26–0.498 g L−1 d−1 and 0.288–0.864 d−1, respectively. In general, the elemental analysis and higher heating value of microalgae biomass for the three species were independent of the culture medium used for its growth, while their lipids and sugars content depended upon the species type and culture medium used in the cultivation. “La Orden” microalga was selected (given its best adaption to the climatic conditions) to study the biomass productivity and growth rate in two exterior photobioreactors (100 L column and 400 L flat panel), using FM as a medium, obtaining values of 0.116–0.266 g L−1 d−1 and 0.360–0.312 d−1, respectively. An automation and control system was designed to operate the exterior photobioreactors pilot plant. The lipid content of this microalga in these photobioreactors was lower than in the laboratory one, with a fatty acids profile with predominantly palmitic, oleic, linoleic and linolenic acids. Also, the fresh biomass collected from these photobioreactors was studied in a batch type digestion process for biogas production, obtaining a CH4 yield of 296 ± 23 L CH4 kgVSS−1 added with a reduction in percentage of COD and vs. of 50 ± 1% and 50 ± 1.7%, respectively.

Multi-scale modeling of intensive macroalgae cultivation and marine nitrogen sequestration

Multi-scale macroalgae growth models are required for the efficient design of sustainable, economically viable, and environmentally safe farms. Here, we develop a multi-scale model for Ulva sp. macroalgae growth and nitrogen sequestration in an intensive cultivation farm, regulated by temperature, light, and nutrients. The model incorporates a range of scales by incorporating spatial effects in two steps: light extinction at the reactor scale (1 m) and nutrient absorption at the farm scale (1 km). The model was validated on real data from an experimental reactor installed in the sea. Biomass production rates, chemical compositions, and nitrogen removal were simulated under different seasons, levels of dilution in the environment and water-exchange rate in the reactor. This multi-scale model provides an important tool for environmental authorities and seaweed farmers who desire to upscale to large bioremediation and/or macroalgae biomass production farms, thus promoting the marine sustainable development and the macroalgae-based bioeconomy.

Model-Based Prediction of Perceived Light Flashing in Recirculated Inclined Wavy-Bottomed Photobioreactors

Microalgae biomass production rate in short light-path photobioreactors potentially can be improved by mixing-induced flashing light regimes. A cascade photobioreactor features a thin liquid layer flowing down a sloping, wavy-bottomed surface where liquid flow exhibits peculiar local recirculation hydrodynamics, potentially conducive to an ordered flashing light regime. This article presents a model-based analysis of the frequency distribution of perceived irradiance in said wavy-bottomed photobioreactor. The model combines a Lagrangian description of the motion of individual cells, in turn derived from the hydrodynamic parameters of the photobioreactor extracted from an experimentally validated Computational Fluid Dynamic model, with a simplified description of the irradiance field across the culture thickness, down to the spectral analysis of perceived irradiance. The main finding of the work is that the wavy bottomed photobioreactor provides a ‘robust’ spectral excitation to the circulating microalgae up to 3 Hz frequency, while in flat panels and bubble columns excitation decays evenly at a 24 db/octave rate. This analysis paves the way to improving the light flashing performance of the wavy-bottomed photobioreactor with respect to geometry (cavity size and installation inclination) and operation (flow rate).

Effect of Dilution on Nitrogen Removal from Ammonia Plant Effluent using Chlorella vulgaris and Spirulina platensis

In this study, the removal of nitrogen from effluent of ammonia plant by Chlorella vulgaris and Spirulina platensis was investigated. For this purpose, microalgae were cultivated in three diluting percentage of the wastewater (1, 3, and 5%) at 29±1 ◦C and light intensity at surface of culture were adjusted to 150 µmol photon / (m2. s). The results showed that Spirulina platensis is more capable than Chlorella vulgaris to grow in high levels of total nitrogen concentration. Also, maximum biomass production rate happened in 1% diluted samples for Chlorella vulgaris and 3% for Spirulina platensis. Furthermore, Chlorella vulgaris reduce total nitrogen concentration up to 55%. This value for Spirulina platensis was about 96%. However, for both species the removal of nitrogen in 1% diluted wastewater was maximum. According to the results of diluted wastewater of ammonia plant, it is a suitable culture medium for microalgae and it can be used to remove the nitrogen before entering the wastewater in nature.

Transcriptomic resources for prairie grass (Bromus catharticus): expressed transcripts, tissue-specific genes, and identification and validation of EST-SSR markers

BackgroundPrairie grass (Bromus catharticus) is a typical cool-season forage crop with high biomass production and fast growth rate during winter and spring. However, its genetic research and breeding has remained stagnant due to limited available genomic resources. The aim of this study was to generate large-scale genomic data using high-throughput transcriptome sequencing, and perform a preliminary validation of EST-SSR markers of B. catharticus.ResultsEleven tissue samples including seeds, leaves, and stems were collected from a new high-yield strain of prairie grass BCS1103. A total of 257,773 unigenes were obtained, of which 193,082 (74.90%) were annotated. Comparison analysis between tissues identified 1803, 3030, and 1570 genes specifically and highly expressed in seed, leaf, and stem, respectively. A total of 37,288 EST-SSRs were identified from unigene sequences, and more than 80,000 primer pairs were designed. We synthesized 420 primer pairs and selected 52 ones with high polymorphisms to estimate genetic diversity and population structure in 24 B. catharticus accessions worldwide. Despite low diversity indicated by an average genetic distance of 0.364, the accessions from South America and Asia and wild accessions showed higher genetic diversity. Moreover, South American accessions showed a pure ancestry, while Asian accessions demonstrated mixed internal relationships, which indicated a different probability of gene flow. Phylogenetic analysis clustered the studied accessions into four clades, being consistent with phenotypic clustering results. Finally, Mantel analysis suggested the total phenotypic variation was mostly contributed by genetic component. Stem diameter, plant height, leaf width, and biomass yield were significantly correlated with genetic data (r > 0.6, P < 0.001), and might be used in the future selection and breeding.ConclusionA genomic resource was generated that could benefit genetic and taxonomic studies, as well as molecular breeding for B. catharticus and its relatives in the future.

Evaluation of Arsenic and Nutrients Uptake of Tomato Plant at Various Arsenic Concentrations of Irrigation Waters

ABSTRACT Under various Arsenic (As) loads, growth of the tomato plant and changes in elemental uptake were investigated in this experimental study. Plants were transplanted into the As free soils and the loads of As were increased gradually with irrigation. The root and stem dry weights (DW) steadily increased with the increase of As concentration up to 1.5 mg L−1, while the DW dropped to lower than the control plant’s DW when the As concentration was higher than mg L−1. Although the leaves DW variations for the studied As concentrations were negligible, As application to the tomato plants positively affected the biomass amount of leaf. Considering the decrease in root/shoot ratio, the root growth was more promoted at low As concentrations, while the effect of As on the production rate of aboveground biomass could be neglected. When the As concentration was increased from 0.5 mg L−1 to 3.0 mg L−1, average 90% of the total applied As to the plants was accumulated in the root and As content in the root was enhanced about four times. Significantly higher levels of N, K, Mg, and Ca in the aerial parts of tomato than in roots were determined while the level of P was about equal in the tissues. Among the tissues, the lowest microelements; Cu, Mn, Fe, and Zn concentrations were determined at the root of control plant. However, especially at high As loads, the increase in the amount of microelements in the root was considerably higher compared to the stem and leaf.

Nutrient recovery and microalgae biomass production from urine by membrane photobioreactor at low biomass retention times

Urine has been considered as an ideal nutrient source for microalgae cultivation thanks to its composition containing the high concentrations of nitrogen and phosphorus. Herein, the microalgae growth in urine was evaluated in a lab-scale membrane photobioreactor (MPBR) system. This work aimed to validate the influence of low biomass retention times (BRT) (10, 7, 5, 3, 2 d) on nutrient remediation and biomass productivity. It revealed that BRT of 7 d resulted in synergistically high biomass production (biomass productivity of 313 mg/L.d) and removal rates (TN of 90.5 mg/L.d and TP of 4.7 mg/L.d). Notably, the short BRT of 2–5 d was not sufficient to trigger actively growing microalgae and thus reduced biomass production rate. In addition, as operated at a low flux of 2 L/m2.h, MPBR system required no physical cleaning for 100 days of operation. The BRT-dependent biomass concentration played a pivotal role in changing the fouling rate of MPBR; however, the fouling is reversible in the MPBR system under the low flux condition.

Highly effective removal of presence of toxic metal concentrations in the wastewater using microalgae and pre-treatment processing

Cultivation of the microalgae in the wastewater has gained profound interest in recent years owing to the significant advantages like removal of nutrients from the wastewater. In general, the growth of the microalgae Coelastrella sp. on the swine wastewater is effective despite the presence of pollutants. The current study discusses the removal of concentration of nitrate, ammonia and phosphorous in the wastewater. Further, the biomass productivity and lipid content of Coelastrella sp. were also determined. Based on the procured results, the concentrations of the total phosphorus and ammonia nitrogen were decreased with the culturing duration. On the other hand, the copper oxide recorded the spike pattern along the cultured time. In contrast with the content of the ammonia and copper inhibiting the growth of the Coelastrella sp., with regard to the biomass and lipid productivity rate, the pre-treated wastewater reported superior growth rate of microalgae then untreated water. Aeration pre-treatment reduced the ammonia and copper contents in the wastewater which enable the impressive growth rate. The obtained average biomass and lipid productivity were 81.5 mg/ld and 19.5 mg/ld, respectively.