Determination of individual chain length and chain-length distribution of polyphosphates in microalgae by 31P-DOSY-NMR

Due to its ecological and biotechnological relevance, polyphosphate in microalgae is currently the focus of intense research. Numerous biological functions are performed by or dependent on polyphosphate, and they depend, among other factors, on its chain length. Chain length determination is important for understanding polyphosphate metabolism and for maximizing intracellular polyphosphate abundance per unit weight of biomass. 31P-DOSY NMR virtually separates various polyphosphate polymers in a mixture based on different translational diffusion coefficients. The diffusion coefficient of a polyphosphate molecule correlates with its molecular weight, enabling determination of individual chain lengths. Moreover, the polydispersity index can also be uniquely determined by DOSY as a measure of the overall chain-length distribution of polyphosphates. By contrast, conventional 31P NMR is only able to estimate the average chain length of the entire polyphosphate pool. Therefore, DOSY provides the opportunity to deepen our insight into polyphosphate metabolism and dynamics in algal biomass

Amendment of poor soil substrate by biochar saturated with biofertilizers (algae, manure) for sustainable production of relevant Palestinian and German crop plants Solanum lycopersicum L. and Hordeum vulgare L.

Soil degradation is a global problem that affects many regions and communities, resulting in poor and stress-prone marginal soils. The potentially positive effects of carbon and nutrient content increase through the addition of nutrient-saturated biochar were investigated on poor and saline substrate in experiments with tomato and barley. Biochar treatments were applied to nutrient- and carbon-poor sandy substrates in two greenhouse pot experiments. Biochar mixed with biofertilizers (algae & pig manure) at three total carbon content levels (0.1, 0.3, 0.5 % C-concentration) was applied to test its effects on tomato growth and soil properties during early growth stages. As a follow-up, carbon addition was increased to 2% via a biochar-sheep manure mixture to test its effect on growth parameters and quality of two barley cultivars (Palestinian & German). Results showed that increasing mineral-fertilizer saturated biochar concentration up to 0.5 % total C in saline soil (4 EC) increased tomato total fruit numbers but delayed the ripening process (24% red fruits in untreated pots, 15% in treated pots). In saline environment, biochar-pig manure mixture led to the highest tomato shoot dry weight (41g) compared to 0% biochar treatments (31g). Increased biochar amount (up to 2%) led to increased shoot fresh weight of up to 1.7g in the German barley cultivar after a 1-month growth period, compared to non-treated (0% biochar) pots at 0.9g, respectively. Increasing biochar up to 2% increased the soil water-holding capacity by up to 17% compared to 0% biochar control. In conclusion, nutrient-saturated biochar constitutes a sustainable solution to condition substrates to improve the quality and fertility of the soil by helping to close the nutrient cycle and increasing the water hold capacity, especially in carbon-poor soil substrate. Further up-scaled greenhouse and field experiments are needed to evaluate longer-term effects on yield and soil parameters

The potential impact of an implementation of microalgae-based wastewater treatment on the energy balance of a municipal wastewater treatment plant in Central Europe

Integration of a photobioreactor for WWT by microalgae is calculated as a future alternative for cost-efficient and environmentally-friendly nutrient removal for municipal WWTPs. High growth rates and higher biogas yields (compared to conventional sewage sludge) of algal biomass can significantly improve WWTP energy balances.This study focuses on temperate climate zones with changing seasons and discusses energy potential of microalgae-enhanced wastewater treatment for an existing WWTP (32,000 PE) in Central Germany. For WWTP-dimensioning and determination of energy-rich biomasses for anaerobic digestion and CHP, actual influent load data was used and calculation was carried out according to valid regulations. Algae growth figures are based on pilot-scale test series from Germany and correspond to the relevant climatic and local process conditions. Computed results show a shift in the energy balance from a current energy demand of 662,173 kWh a-1 to an energy production of approx. 1,9 MWhel. a-1 and 1 MWhth. a-1

In Vitro Assessment of Salinity Stress Impact on Early Growth in Ten Certified Palestinian Barley Cultivars (Hordeum vulgare L.) Potentially Suitable for Cultivation on Former Quarry Substrates

Salinity is a major constraint for crop health and productivity, particularly on arid, semiarid, and otherwise marginal soils, such as quarry residue. Quarries are a main pillar of national income in Palestine but have a long-lasting toll on the environment. We examined barley (Hordeum vulgare L.), another pillar of the Palestinian economy and one of the most important crops in the world, in this regard for its tolerance to salinity stress. This study is the first to evaluate the impact of salinity (50, 85, 120, and 175 mM NaCl) on seed germination, early growth stage, and morpho-anatomy on ten pre-selected certified Palestinian barley cultivars (Baladi, Improved Baladi, Rihan, ICARDA 1, ICARDA 15, ACSAD 68, ACSAD 176, ACSAD 1417, ACSAD 1732, and ACSAD 1744) to assess their potential for a successful growth start under adverse saline conditions. In addition, soil samples from quarries in Hebron governorate were randomly selected and tested for salinity level, elec-trical conductivity, and total of soluble salts for a first rough overview of options for applying our results, since local data are often scarce or outdated. The examined soil samples reached electrical conductivity (EC) ranges of 1.81 × 10−4–9.071 × 10−4 dS m−1, which are below the normal EC (11–57 × 10−4 dS m−1). This result may contraindicate the hypothesis that quarry lands always suffer from salinity stress. Cultivars such as ACSAD 68 and Icarda 15 proved very sensitive to higher salinity stress with high G50 (time point when 50% of seeds have germinated) at 4.4 d, with 120 mM NaCl (ACSAD 68) or incalculable amounts (Icarda 15) and just 50 and 20% total germination, respec-tively. Concentrations of 175 mM NaCl were found in ACSAD 176 and Improved Baladi (no G50, 37 and 30% germination, respectively). Some cultivars showed a moderate to high resilience to sa-linity, such as ICARDA I, ACSAD 1417, and ACSAD 1744, which reached > 80% seed germination at 120 mM NaCl and >60% at 175 mM NaCl, and G50 within 1.5–2.2 days; the most resilient was ACSAD 1732 with G50 80% at 175 mM NaCl. This is strongly supported by the monitored growth parameters. In conclusion, ACSAD1732 and Icarda 1 cultivars are highly recommended for cultivation in areas of low precipitation and high salt accumulation. In addition, the land and/or soil of quarries, their landfills, and nearby areas in Palestine may be fit for barley cultivation with recommended cultivars regarding salinity stress

Microalgae and Biochar Agro-Fertilization of the Palestinian Rehan Barley Cultivar under Salinity Stress

The efficient transfer of nutrients to plants in the form of biofertilizers on poor substrate was investigated. Biochar and dried algae biomass as well as mineral fertilizer were used to test the growth of the Palestinian ‘Rehan’ barley cultivar under salinity stress (4, 8, and 16 mS/cm EC). Rehan cultivar showed resilience to moderate levels of salinity and could still grow under high salinity stress (16 mS/cm EC). Rehan barley possessed better growth at early growth stage under the applied biofertilizers such as dried freshwater algal biomass (Chlorella vulgaris) and nutrient-laden biochar. It showed better growth than wheat (ssp. scirocco) under the same conditions. Its growth was highly improved by biochar treatment in low and moderate salinity conditions. Moreover, the combined effect between biochar and dried algae biomass could improve Rehan barley growth, but less than the effect of each biofertilizer separately. The biofertilizers affected most plant growth parameters under the salinity level of 4 and 8 mS/cm EC positively, while the growth declined again at 16 mS/cm EC. Overall, the biochar treatment showed the same effect as the mineral fertilizer on most of the parameters. The dried algae biomass and biochar also affected soil conditions. The highest soil water content (15.09%) was found in algae biomass treatments with 16 mS/cm EC. Biochar with 8 and 16 mS/cm EC had the highest pH value (8.63) near the rhizospheres. The nitrogen level was highest in the bottom soil sample (0.28 g N/kg soil) for biochar with 0 and 4 mS/cm EC. Meanwhile, the phosphate concentration was the highest (3.3 mg PO3−2/kg soil) in algae fertilizer treatments with 0 mS/cm EC in the bottom soil sample and lowest (4.14 mg PO3−2/kg soil) for the biochar with 8 mS/cm EC. The dried algae biomass and the biochar treatments can subsequently be viewed as conditioner substrates for improving the quality and fertility of the soil. Where possible, they should be considered as complement or replacement of mineral and manure fertilization to improve the impact on soil and environment

The effects of algae fertilizer on wheat root morphology

Global food supply is largely dependent on staple crops; amongst them bread wheat (Triticum aestivum, L.). To secure quantity and quality of food worldwide, new sustainable agricultural strategies are needed. An option is the replacement of finite rock phosphate with renewable phosphorus sources, for example algal biomass. Wheat roots can acquire similar amounts of phosphorus from algae as compared to rock phosphate sources, but show alterations in morphology1. Therefore we hypothesize that (1) algal phosphorus is available to wheat and is taken up by the root systems directly, and (2) differences in root morphology between rock phosphate and algal biomass reflect a change in uptake mode. Our approach will combine chemical characterization of algal fertilizer and its degradation with mass balance analyses and plant phenotyping experiments to quantify the phosphorus forms and their uptake mode by wheat and its root system. EcoFABs (Ecosystem FABbrications) will be utilized for sterile cultivation of single plants of wheat and its model Brachypodium, treated with algae. EcoFABs were developed for live-analysis of the root and the rhizosphere by microscopy in controlled micro-environments2. Temporally resolved analysis of the medium will support the exploration of dynamics in phosphorus pools and the identification of inorganic and organic forms used by plants. We expect that algal nutrients can and will be utilized by the plant and that we will observe changes in morphology, metabolism and exudate composition in and around the root. The overall aim is to identify traits that will allow efficient application of algae fertilizer for agricultural systems.1. C. Schreiber et al., J. Appl. Phycol. 30, 2827–2836 (2018).2. J. Gao et al., J. Vis. Exp., 1–16 (2018)

The effects of algae fertilizer on wheat root morphology elucidated using modeling, phenotyping and metabolomics

One of the big challenges facing humanity is securing food and feed for future generations in a sustainable bioeconomy. The way fertilizer is used today aims at high yields without adequately considering the needs of plants and the preservation of our environment. The microalgae Chlorella vulgaris has been successfully used as a vector system to recycle phosphorus. Our group found additionally that C. vulgaris can fertilize wheat and modify the root architecture. The underlying mechanisms have not yet been investigated, and as a consequence, we hypothesize that: (1) nutrients from algae are available to wheat (Triticum aestivum L.) root uptake; (2) roots respond to algae fertilizer with changes in root architecture and morphology that are different to conventional fertilizer; and (3) active response of roots to algal nutrients is reflected in an alternate mode of nutrient uptake. We are analyzing single plants in highly controlled microenvironments that allow the direct observation of morphological changes at the root micro- and macroscales. Simultaneously, we quantify changes in the phosphate pools released and transformed from algal components into the medium, their uptake from the medium, and their incorporation into the plant. These dynamics will allow the identification of the fertilizing phosphate components of the algal biomass. Their separation into different organic and inorganic fractions will allow the identification of the specific components available to root uptake. Effects of components on roots and the plant’s nutrition will be assessed by metabolomics. We are using the genetic model for wheat, Brachypodium distachyon, because it is suited to phenotyping, genotyping and interpretation of metabolomics. A better understanding of the interface between algal nutrients and the root may enable future agricultural applications with sustainable use of algal biomass after it has been mined for other valuable compounds