Biomass Production Efficiency Research Articles

Vascular bundle cell-specific expression of a phosphate transporter improves phosphate use efficiency of transgenic Arabidopsis without detrimental effects

Constitutive overexpression of phosphate (Pi) transporter family 1 often results in the accumulation of toxic levels of Pi, which causes growth retardation in plants. In contrast, we had previously reported that root epidermis-specific overexpression of the phosphate transporter TaPT2 in Arabidopsis leads to improved growth and Pi use efficiency. In the present study, we used promoters AtHKT1;1 and SKOR, which are predominantly expressed in the vascular bundle tissues, to overexpress TaPT2. Transgenic lines exhibited increased shoot growth compared to wild type plants under normal- and low-Pi conditions, along with elevated root Pi and total P content, and higher xylem sap Pi concentration, specifically under low-Pi conditions. This was attributed to moderate Pi accumulation in the xylem parenchyma cells, enhancing the Pi uploading capacity to the xylem. SKOR-TaPT2, however, did not complement pho1 mutant, which was defective in uploading Pi to the xylem. The transcriptional levels of VPT1 and VPT3, which are responsible for transporting excess Pi into a vacuole, were upregulated in SKOR promoter lines under normal-Pi conditions. Our results suggested that root vascular bundle-specific expression of TaPT2 is another promising strategy for increasing biomass production, Pi uptake, and Pi use efficiency while preventing growth retardation in transgenic plants.

Sustainable remediation of piggery wastewater using a novel mixotrophic Chlorella sorokiniana Cbeo for high value biomass production

Piggery wastewater (PW) contains high density of organic carbon (COD), nitrogen (NH4+-N and TN) and phosphorous (TP), which are essential nutrients for microalgae growth. This work was attempted to use a newly isolate Chlorella sorokiniana Cbeo for recovery these compounds into its biomass via mixotrophic cultivation. Critical factors including level of ammonia, C/N ratio, pH, light intensity, sterilized/unsterilized media, and indoor/outdoor cultivations affecting biomass production and nutrients removal efficiencies were investigated. Data revealed that C. sorokiniana Cbeo achieved the optimal growth in the unsterilized medium at NH4+-N concentration, C/N ratio, initial pH, and light intensity of 250mg/L, 10/1, 7, and 150 μmol/m2/s, respectively. Under the optimal conditions, dry cell weight (DCW) reached the maximal level of 4.30g/L, which was slightly higher than 4.14g/L determined for the sterilized medium. In 30 L-scale photobioreactor, C. sorokiniana Cbeo grown under indoor and outdoor achieved DCW of 3.61 and 3.19g/L, respectively. COD, NH4+-N, TN, TP removal efficiencies for both conditions were determined as 91.9–96.7, 96.6–99.7, 96.2–96.4, and 98.2–100%, respectively. The C. sorokiniana Cbeo biomass contained 14–27% lipid, 25–32% carbohydrate, 44–48% protein, and 0.25–0.97% lutein. Interestingly, α-Linolenic acid (C18:3n3) was 19.84 –27.0% of the total fatty acids. C. sorokiniana Cbeo is the promising algal strain for development of a sustainable biorefinery of PW.

Optimizing biomass production and photochemical efficiency of in vitro-grown Capsicum annuum L. using gas-permeable membrane flasks

Optimizing biomass production and photochemical efficiency of in vitro-grown Capsicum annuum L. using gas-permeable membrane flasks

Comprehensive Analysis of Miscanthus Research: Sustainable Biomass and Bioenergy Through Knowledge Mapping

Miscanthus grass species have gained global research attention in the fields of biomass and bioenergy, witnessing remarkable advancements in the 21st century. This study systematically searched and selected relevant literature on primary research involving Miscanthus species, published between 2007 and 2023, from the China National Knowledge Infrastructure and Web of Science core databases. Utilizing CiteSpace as a bibliometric tool, the study generated quantitative statistics and performed data analysis on the selected articles. The examination covered publication trends, national and author publication outputs, author and journal co-citations, keyword research hotspots, and the temporal evolution of research topics in the Miscanthus research field, offering empirical support for future in-depth investigations and innovation in Miscanthus spp. The research findings reveal the following insights: (1) Publication trends can be divided into two phases (stable growth and fluctuating decline), with recent trends maintaining a relatively high level. (2) A collaborative publication network, led by core authors such as Zili Yi, John Clifton-Brown, and Iris Lewandowski, has been established, characterized by a diverse research focus and close cooperation. (3) Research hotspots encompass several aspects, including biomass production yield, efficiency, and energy products of Miscanthus spp., ecological restoration, genetics, plant physiological research, and chemical components. The primary species investigated are Miscanthus×giganteus, Miscanthus sinensis, Miscanthus floridulus, and Miscanthus lutarioriparius.

Oriented regulation of earthworm production and vermicompost quality by carbon bioavailability management

Vermicomposting is an efficient bioconversion technology for recycling nutrients from organic waste materials. The biodegradability of raw materials has a significant impact on the earthworm transformation product. However, the management of carbon bioavailability is often overlooked during the vermicomposting process due to the varying degradability of C-rich source in different organic waste. This research aims to investigate the impact of different bioavailable carbon compositions on vermicomposting and to develop a strategy for efficient carbon management. The study involved systematic vermicomposting using four different biodegradable carbon sources (pineapple peels, rice straw, tomato straw, and sawdust) with varying carbon‑nitrogen ratios (ranging from 24 to 42). The earthworm production and vermicompost quality were comprehensively evaluated, along with the influence of carbon components on microbial community structure. The results indicated that the optimal vermicomposting treatments were achieved at PCM24, RCM30, TCM30, and MCM30 treatments. Maintaining an approximate ratio of 1:(0.5–1.3) between available and recalcitrant carbon components based on the optimal carbon‑nitrogen ratio was found to be optimal for regulating vermicomposting products. Increasing the proportion of available carbon enhanced the quality of vermicompost fertilizer, while a higher proportion of recalcitrant carbon could improve earthworm biomass production efficiency. Labile carbon proportion I (LCP1) and available carbon component (ACC) were identified as key indicators in influencing the formation of microbial community structure. Different carbon compositions led to the specific development and formation of microbial communities, further resulting in significant variations in vermicompost quality under the mediation of microbes. This study, for the first time, clarifies the impact of vermicomposting performance and microbial community from the perspective of carbon bioavailability, which is of great significance for the oriented regulation the vermicomposting efficiency and product in practice.

Bioderived nanostructure and their functional contribution in immobilization of cellulolytic enzymes for improving biosensing application

Cellulases fall under the biocatalyst and one of industrial enzymes which is highest in demand due to diverse and huge applications. It plays major role in cellulosic bioenergy production achieving biomass hydrolysis for sugar and energy production. Inspite of prime enzyme in demand and key application in cellulosic energy production, this group of enzymes are suffering with lower enzyme activity and poor functional stability which directly influence the poor bioconversion efficiency of cellulosic biomass and bioenergy production. This is one the crucial issue which blocks the suitable commercial implementation of bioenergy at global scale. Therefore, researches in this particular area accelerate and speed in up to improve the functional stability of this enzymes. Immobilization of cellulolytic enzymes on nanomaterials is emerging as one of the very promising approaches in this area and supposed to have sustainable future towards improving the functional stability of cellulase enzymes via nanostructure based immobilization. Due to unique physicochemical properties and mode of origin nanoform, these nanomaterials can be an effective tool to enhance the catalytic stability of the cellulase enzymes. Therefore, the present reviews explore the possibilities of immobilization of nanomaterials as one of the promising tool to improve cellulosic bioenergy production. Additionally, one of the prime focus of the review is also based on the types, methods and mode of immobilization using different nanomaterials and analyzed the existing advantages and disadvantages of the process. Moreover, the work has also been highlighted the existing limitation and the future suggestion to improve the process applicability.

Flooding tolerance, biomass production, and leaf nitrogen assimilatory efficiency in 29 diverse willows (Salix spp.) genotypes during early growth

ABSTRACT Willows are frequently planted as unrooted cuttings in flood-prone areas. The occurrence of a flooding episode during the early stages of the plantation causes diverse morphological and physiological changes in willows. Thus, it is important to identify traits correlating to flooding tolerance to be used to breed genotypes with enhanced tolerance to this stress. In addition, flooding can change nitrogen absorption in plants, altering leaf nitrogen concentration. These changes could influence the photosynthetic activity, and ultimately, the growth of plantations. The aims of this work were: (i) to identify traits that increase flooding tolerance in willows during early growth and (ii) to analyze the effects of flooding on Assimilatory Nitrogen Use Efficiency (ANUE, measured as foliar biomass: foliar nitrogen concentration ratio). Two-month-old plants growing in pots of 29 willow genotypes were flooded with water covering 80% of the stem, for 43 days. At the end of this period, the flooding tolerance index (ratio between the flooded plant biomass to the non-flooded plant biomass) ranged between 39% and 103%. Flooding tolerance had a significant and positive correlation to plant height, diameter, total biomass, growth rate, leaf area, leaf number, and basic wood density. ANUE decreased in flooded plants in most genotypes, despite the increase in leaf nitrogen concentration. This implies that flooded plants were less efficient in the use of nitrogen to produce leaf biomass than the non-flooded treatment. These results are relevant for the selection of flooding tolerance in young willow plants obtained from rootless cuttings.

Energy efficiency of Silphium perfoliatum and Helianthus salicifolius biomass production

Silphium perfoliatum L. and Helianthus salicifolius A. Dietr are perennial herbaceous crops (PHC) that have recently attracted much attention. This study aimed to determine the energy input, the yield energy value, and the biomass production energy efficiency for the two prospective PHC species depending on the type of fertilizer (liquid digestate and mineral fertilizers) and the nitrogen fertilization level (0, 85 and 170 kg ha−1 N) in three consecutive growing years (2019–2021). S. perfoliatum produced a 14.1 % higher biomass yield energy value (142.3 GJ ha−1 y−1 on average) than H. salicifolius. However, the production of S. perfoliatum also required 22.8 % higher mean energy input (11.3 GJ ha−1 y−1) compared to H. salicifolius. As a result, the mean energy ratio for H. salicifolius (15.2) was 8.6 % higher than for S. perfoliatum. The highest energy ratios for H. salicifolius and S. perfoliatum were 29.7 and 22.8, respectively. Liquid digestate and mineral fertilization resulted in an increase in the yield energy value compared to plots with no fertilization, but at the same time, it increased the energy input. Therefore, the energy ratio in control plots was higher compared to the variants with fertilization.

Multi-criteria analysis of the continuous operation of a membrane photobioreactor to treat sewage: Modeling and sensitivity analysis

Microalgae-based wastewater remediation is aligned with circular economy principals but successful large-scale facilities are scarce due to the limited knowledge of the interactions between all relevant variables and the scarce development of control and automation systems. Machine learning (ML) methods have the potential predict performance in microalgae photobioreactors, with the aim to optimize it. Some attempts have been performed under controlled lab conditions which prevents the direct application of their results to industrial scale. This study aims to develop ML models for the prediction of nutrient removal, biomass production and photosynthetic efficiency using a database obtained from 1.5-y operation of a pilot-scale membrane photobioreactor (MPBR) that treated sewage. A total of 14 inputs and 6 outputs were selected. Random forests (RF), boosted trees (BT), multilayer perceptron (MLP), support vector machine methods (SVM) were tested. The lowest prediction errors were obtained with the MLP model, allowing the developed tool to be used as an alternative to mechanistic models. Large ranges of data were used, considering the variability of factors in the diurnal cycle whose influence on the variability of the data is usually neglected. Using global sensitivity analysis (GSA), input-output relationships were verified, reflecting relevant number of variables showing significant values of Shapley Indices. Additionaly, partial dependence plots showed both linear and nonlinear depending on the selected inputs and outputs. Finally, using ML models, multi-criteria optimization of operating parameters was performed for two variants: a) optimization of operating parameters (HRT, SRT, and air flowrate (Fair)); and b) optimization of operating parameters and influent nutrient loads (HRT, SRT, Fair, nitrogen and phosphorus loading rates).

Energy-Efficient Production of Microchloropsis salina Biomass with High CO2 Fixation Yield in Open Thin-Layer Cascade Photobioreactors

Lipid production using microalgae is challenging for producing low-value-added products. Harnessing microalgae for their fast and efficient CO2 fixation capabilities may be more reasonable since algal biomass can be utilized as a precursor for various products in a biorefinery approach. This study aimed to optimize the productivity and efficiency of Microchloropsis salina biomass production in open thin-layer cascade (TLC) photobioreactors under physical simulation of suitable outdoor climate conditions, using an artificial seawater medium. Continuous operation proved to be the most suitable operating mode, allowing an average daily areal productivity of up to 27 g m−2 d−1 and CO2 fixation efficiency of up to 100%. Process transfer from 8 m2 to 50 m2 TLC photobioreactors was demonstrated, but with reduced daily areal productivity of 21 g m−2 d−1 and a reduced CO2 fixation efficiency, most probably due to increased temperatures at midday above 35 °C. An automated overnight switch-off of the circulation pumps was implemented successfully, reducing energy and freshwater requirements by ~40%. The ideal conditions for continuous production were determined to be a dilution rate of 0.150–0.225 d−1, pH of 8.5, and total alkalinity of 200–400 ppm, facilitating efficient pilot-scale production of microalgal biomass in TLC photobioreactors.

Economic and energy efficiency of resource-saving technology for switchgrass cultivation

Purpose. The study aimed to compare the efficiency of the resource-saving technology with the conventional technology for switchgrass cultivation using the developed methodology for assessing the economic and energy efficiency. Methodology / approach. The study used general and special methods, including the methodology of scientific research in agronomy, laboratory determination of dry matter content in biomass, quantitative-weight analysis to establish crop yield, and the authors’ improved methodology for assessing economic and energy efficiency. The research results were statistically processed using variance and comparative analysis. Results. The results of the research on the use of resource-saving cultivation technology in comparison with conventional technology show an increase in switchgrass biomass yield from 14.6 to 15.7 t/ha, an increase in economic efficiency with profitability growth from 73.8 to 79.0 %, and an increase in energy efficiency with a growth of the energy efficiency coefficient by 0.7 – from 4 to 4.7 (average level of energy efficiency) when applying a specific complex of agrotechnical measures. When using resource-saving technology, the average full cost of cultivating switchgrass for six years is 8305.6 UAH/ha, compared to 7952.8 UAH/ha with conventional technology. However, resource-saving technology generates an average sales revenue of 14867.5 UAH/t, which is 1045 UAH/t more than conventional technology (13822.5 UAH/t). Originality / scientific novelty. For the first time, a field experiment was conducted to compare switchgrass cultivation using resource-saving and conventional technologies. The authors have developed a methodology to assess the economic and energy efficiency of cultivating switchgrass. The results indicate that the efficiency of switchgrass biomass production is influenced by improved cultivation technology. The authors have developed a three-dimensional econometric model that demonstrates how the profitability level depends on the chosen switchgrass cultivation technology. Practical value / implications. The research results have practical significance as they have led to the development of a methodology and evaluate the economic and energy efficiency of switchgrass cultivation. These results will be useful for agrarian enterprises to save resources.

Assessing the Impact of Hexavalent Chromium (Cr VI) at Varied Concentrations on Spirulina platensis for Growth, Metal Sorption, and Photosynthetic Responses.

Spirulina platensis, a photosynthetic cyanobacterium, has garnered attention for its potential role in environmental remediation due to its ability to absorb and metabolize toxic heavy metals. Understanding its response toward toxicity of one of the most common contaminants, Cr(VI) is crucial for assessing its efficacy in bioremediation efforts. This study aims to investigate the physiological and biochemical responses of Spirulina platensis to varying concentrations of Cr(VI) from 0.5 to 5ppm, shedding light on its potential as a bioindicator for environmental contamination and its suitability for bioremediation purposes. The impact of Cr(VI) on cell density, biosorption, pigment levels, nutrient content, fluorescence response, and photosynthetic efficiency was examined. The study revealed a gradual reduction in cell density, biomass production, and biosorption efficiency with increasing Cr(VI) concentrations. Pigment levels, carbohydrate, protein, and lipid content showed significant decreases, indicating physiological stress. Fluorescence response and photosynthetic efficiency were also adversely affected, suggesting alterations in electron transfer dynamics. A threshold for chromium toxicity was observed at 0.5ppm, beyond which significant physiological disturbances occurred. This investigation highlights the sensitivity of Spirulina platensis to Cr(VI) toxicity and its potential as a bioindicator for heavy metal contamination. Metal sorption was highest in 0.5ppm Cr(VI) with 56.56% removal. Notably, at lower concentrations, Cr(VI) acted as an intermediate electron acceptor, enhancing the electron transport chain and potentially increasing biomass under controlled conditions. The findings underscore the importance of understanding the mechanisms underlying heavy metal stress in microalgae for effective environmental remediation strategies. The research highlights the dual role of chromium(VI) in influencing S. platensis, depending on the concentration, and underscores the importance of understanding metal ion interactions with photosynthetic organisms for potential applications in bioremediation.

Biomass production and nutritional efficiency in short rotation eucalypt clone plantations for energy in north-east Brazil

Selecting adapted hybrids with greater efficiency in the use and return of nutrients is essential to ensure the success of forestry activities. Although topics on the nutritional sustainability of eucalypt biomass harvesting have frequently been discussed, few studies have focused on short rotation eucalypt clonal plantations (aimed at energy production), especially in conditions of nutrient scarcity and water limitations in Brazil. Therefore, our objective was to evaluate the nutritional efficiency and sustainability (for nitrogen (N), phosphorus (P) and potassium (K)) of six eucalypt clones in short rotation cultivation in the north-east of Brazil, considering different harvesting scenarios and using the Eucalyptus urophylla species as a reference, which is traditionally planted in the study region. Direct quantification of the biomass of 21 trees of each clone was carried out at 5 years of age. The clones did not affect the accumulation of total biomass (on average, 199.9 Mg ha−1). The 1296 and 1355 clones provided lower biomass export and greater nutritional efficiency, favouring an increase in the potential number of rotations (PNR) for P and a reduction in the N removal rate (RR). However, the VM58 clone showed higher biomass export and lower PNR. Thus, clones 1296 and 1355 are more favourable, while clone VM58 is less favourable to nutritional sustainability under the studied conditions. Nitrogen and K may cause productivity limitations in future rotations in whole-tree harvesting systems. Adopting more conservationist harvesting systems with removing only the stemwood or stemwood with bark can optimise the potential of clones, minimise the need to add fertilisers and ensure maintenance of the site’s productivity.

Exploring the impact of magnetic fields on biomass production efficiency under aerobic and anaerobic batch fermentation of Saccharomyces cerevisiae

In this work, the effect of moderate electromagnetic fields (2.5, 10, and 15 mT) was studied using an immersed coil inserted directly into a bioreactor on batch cultivation of yeast under both aerobic and anaerobic conditions. Throughout the cultivation, parameters, including CO2 levels, O2 saturation, nitrogen consumption, glucose uptake, ethanol production, and yeast growth (using OD 600 measurements at 1-h intervals), were analysed. The results showed that 10 and 15 mT magnetic fields not only statistically significantly boosted and sped up biomass production (by 38–70%), but also accelerated overall metabolism, accelerating glucose, oxygen, and nitrogen consumption, by 1–2 h. The carbon balance analysis revealed an acceleration in ethanol and glycerol production, albeit with final concentrations by 22–28% lower, with a more pronounced effect in aerobic cultivation. These findings suggest that magnetic fields shift the metabolic balance toward biomass formation rather than ethanol production, showcasing their potential to modulate yeast metabolism. Considering coil heating, opting for the 10 mT magnetic field is preferable due to its lower heat generation. In these terms, we propose that magnetic field can be used as novel tool to increase biomass yield and accelerate yeast metabolism.

Enhanced biomass production and harvesting efficiency of Chlamydomonas reinhardtii under high-ammonium conditions by powdered oyster shell

Chlamydomonas reinhardtii prefers ammonium (NH4+) as a nitrogen source, but its late-stage growth under high-NH4+ concentrations (0.5 ∼ 1 g/L) is retarded due to medium acidification. In this study, oyster shell powders were shown to increase the tolerance of C. reinhardtii to NH4+ supplementation at 0.7 g/L in TAP medium in 1-L bubble-column bioreactors, resulting in a 22.9 % increase in biomass production, 62.1 % rise in unsaturated fatty acid accumulation, and 19.2 % improvement in harvesting efficiency. Powdered oyster shell mitigated medium acidification (pH 7.2–7.8) and provided dissolved inorganic carbon up to 8.02 × 103 μmol/L, facilitating a 76.3 % NH4+ consumption, release of up to 189 mg/L of Ca2+, a 42.1 % reduction in ζ-potential and 27.7 % increase in flocculation activity of microalgae cells. This study highlights a promising approach to utilize powdered oyster shell as a liming agent, supplement carbon source, and bio-flocculant for enhancing biomass production and microalgae harvesting in NH4+-rich environments.

Microbial central carbon metabolism in a tidal freshwater marsh and an upland mixed conifer soil under oxic and anoxic conditions.

The central carbon (C) metabolic network is responsible for most of the production of energy and biosynthesis in microorganisms and is therefore key to a mechanistic understanding of microbial life in soil communities. Many upland soil communities have shown a relatively high C flux through the pentose phosphate (PP) or the Entner-Doudoroff (ED) pathway, thought to be related to oxidative damage control. We tested the hypothesis that the metabolic organization of the central C metabolic network differed between two ecosystems, an anoxic marsh soil and oxic upland soil, and would be affected by altering oxygen concentrations. We expected there to be high PP/ED pathway activity under high oxygen concentrations and in oxic soils and low PP/ED activity in reduced oxygen concentrations and in marsh soil. Although we found high PP/ED activity in the upland soil and low activity in the marsh soil, lowering the oxygen concentration for the upland soil did not reduce the relative PP/ED pathway activity as hypothesized, nor did increasing the oxygen concentration in the marsh soil increase the PP/ED pathway activity. We speculate that the high PP/ED activity in the upland soil, even when exposed to low oxygen concentrations, was related to a high demand for NADPH for biosynthesis, thus reflecting higher microbial growth rates in C-rich soils than in C-poor sediments. Further studies are needed to explain the observed metabolic diversity among soil ecosystems and determine whether it is related to microbial growth rates.IMPORTANCEWe observed that the organization of the central carbon (C) metabolic processes differed between oxic and anoxic soil. However, we also found that the pentose phosphate pathway/Entner-Doudoroff (PP/ED) pathway activity remained high after reducing the oxygen concentration for the upland soil and did not increase in response to an increase in oxygen concentration in the marsh soil. These observations contradicted the hypothesis that oxidative stress is a main driver for high PP/ED activity in soil communities. We suggest that the high PP/ED activity and NADPH production reflect higher anabolic activities and growth rates in the upland soil compared to the anaerobic marsh soil. A greater understanding of the molecular and biochemical processes in soil communities is needed to develop a mechanistic perspective on microbial activities and their relationship to soil C and nutrient cycling. Such an increased mechanistic perspective is ecologically relevant, given that the central carbon metabolic network is intimately tied to the energy metabolism of microbes, the efficiency of new microbial biomass production, and soil organic matter formation.

Drip-tape irrigation depth: water use efficiency, yield and forage quality in maize

Objective: to evaluate the effect of the drip-tape irrigation depth on the efficiency of water use, yield, nutritional quality and profitability of forage maize, a study was established by installing drip-tape at a depths 0.05, 0.15 and 0.30 meters. Design/ Methodology/ Approach: a randomized block experimental design was used. Treatments evaluated consisted of the installation of drip-tape at three depths 0.05, 0.15 and 0.30 m; each treatment in three replicates. The experimental unit was a 15 m2 surface (comprising four 5m-long furrows, with a 0.76 m separation between furrows). Results: results showed that with the drip-tape installed at a depth of 0.15 m, the highest biomass production and water use efficiency were obtained, without modifying the bromatological quality of the forage. However, the best benefit-cost ratio corresponded to the drip-tape installed at 0.3 m, recovering $1.27 for each MXN peso invested in crop production. Limitations/ Implications of the study: water scarcity in arid and semi-arid regions is a global problem, so it is necessary to use irrigation methods that make water use more efficient without reducing crop yield. Findings/conclusions: the installation of the drip-tape at a depth of 0.15 m is recommended, due to the improvement in yield and water use efficiency without affecting nutritional quality of the forage or profitability of maize crop.

High-intensity pulsed-light cultivation of unicellular algae: Photosynthesis continues in the dark

Experiments have shown that photon exploitation efficiency in unicellular algal biomass production under a pulsed-light regime with a high-photon flux is higher than the efficiency under continuous illumination with the same flux. This observation has been explained theoretically to be a consequence of the improved efficiency of exploitation of photons by Photosystem II (PS II) thanks to the combined effect of photon-absorption statistics, a rate-limiting time scale and the size of the PQ pool.Exploiting the same ideas, it is shown in this paper that, under a pulsed-light regime, there is a pulse-time length, for which the average exploitation efficiency of PS II absorbed photons is maximal. Under ideal conditions, this maximum is close to 100%. The optimal pulse-time length is roughly proportional to the size of the PQ pool, NPQ. This is clearly seen for τ (the average time gap between consecutive photons absorbed by the PS II-Chlorophyll antenna) of the order of 1 ms or less (corresponding to a high photon flux and/or a large photon absorption cross-section area of the antenna) and for small NPQ. The width of the plot of efficiency vs. pulse length around the optimum is then small and the optimal pulse length is well defined. As τ is increased beyond 1 or NPQ becomes large, the width grows, allowing for a broad choice of pulse lengths, for which efficiency is very close to the maximum.These observations open the door to future designs of highly productive bioreactors.

Effect on biomass production and phosphorus use efficiency of maize by using citric acid amended di-ammonium phosphate fertilizer

Phosphorus (P) is a critical factor influencing maize (Zea mays L.) development and yield. To explore the influence of P on maize growth, a pot experiment was conducted during the summer of 2021. There were five treatments T1 = No DAP/CA, T2 = 5 ml (80 mg kg−1 soil) DAP, T3 = 5 ml (120 mg kg−1 soil) DAP, T4 = 5 ml (80 mg kg−1 soil) DAP and 2 mM citric acid, T5 = 5 ml (120 mg kg−1 soil) DAP and 2 mM citric acid. Citric acid-amended P fertilizers (i.e., CA and DAP) exhibited significant effects (p < 0.05) on all the parameters studied in comparison to the sole application of DAP. Among phosphorus fertilized treatments, the DAP 120 + CA produced significantly higher biomass yield (16.37 g pot−1), while sole DAP 80 produced lower biomass (10.61 g pot−1); the DAP 120 + CA produced significantly higher plant length (34.273 cm), while sole DAP 80 produced lower plant length (30.467 cm); DAP 80 + CA produced significantly higher phosphorus recovery (25.583%), while sole DAP 120 produced lower phosphorus recovery (19.863%); DAP 120 + CA showed significantly higher phosphorus use (69.565 mg plant-1), while sole DAP 80 showed lower phosphorus use (39.154 mg plant-1); the highest total PUE (40.503%) was recorded in DAP 120 + CA treatment, while sole DAP 80 treatments showed lower PUE (22.743%); and the highest PCN (4.25 mg g-1) was recorded in DAP 120 + CA treatment while sole DAP 80 treatments showed lower PCN (3.69 mg g-1). In conclusion, the use of citric acid-amended P fertilizers (CA and DAP) significantly improved all parameters studied, compared to the sole application of DAP. The DAP 120 + CA treatment showed the highest values for biomass yield, plant length, phosphorus recovery, phosphorus use, total PUE, and PCN, while the sole DAP 80 treatment showed lower values for these parameters. The findings suggest that growing maize using citric acid-amended DAP could be more beneficial to get a higher crop yield of maize. Thus, fertilizer application in maize agriculture can be a technique for boosting both economic and environmental profitability.

Efficient Production of Microalgal Biomass—Step by Step to Industrial Scale

The production of microalgal biomass on a commercial scale remains a significant challenge. Despite the positive results obtained in the laboratory, there are difficulties in obtaining similar results in industrial photobioreactors. Changing the cultivation conditions can affect not only the growth of microalgae but also their metabolism. This is of particular importance for the use of biomass for bioenergy production, including biofuel production. The aim of this study was to determine the biomass production efficiency of selected microalgal strains, depending on the capacity of the photobioreactor. The lipid and ash content of the biomass were also taken into account. It was found that as the scale of production increased, the amount of biomass decreased, irrespective of the type of strain. The change in scale also affected the lipid content of the biomass. The highest values were found in 2.5 L photobioreactors (ranging from 26.3 ± 2.2% for Monoraphidium to 13.9 ± 0.3% for Chlorella vulgaris). The least favourable conditions were found with industrial photobioreactors, where the lipid content of the microalgal biomass ranged from 7.1 ± 0.6% for Oocycstis submarina to 10.2 ± 1.2% for Chlorella fusca. The increase in photobioreactor capacity had a negative effect on the ash content.