Algae Spirogyra Research Articles

Optimizing Algal Oil Extraction and Transesterification Parameters through RSM, PCA, and MRA for Sustainable Biodiesel Production

This study presents a comprehensive optimization of algal oil extraction and transesterification for sustainable biodiesel production. Freshwater Spirogyra algae underwent Soxhlet extraction using n-hexane. response surface methodology (RSM), principal component analysis (PCA), and multivariate regression analysis (MRA) were employed to investigate the effects of biomass–solvent ratio (BSR), algae particle size (APS), and extraction-contact time (E-CT) on algal oil yield (AOY). The extracted oil was then converted to biodiesel via transesterification, and the impacts of the methanol–oil ratio (MOR) and transesterification-contact time (T-CT) on biodiesel conversion efficiency (BCE) were analyzed. Results demonstrate that optimal BSR, APS, and E-CT for maximal AOY are 1:7, 400 µm, and 3–4 h, respectively. For transesterification, a MOR of 12:1 and a T-CT of 4 h yielded the highest BCE. Predictive models exhibited exceptional accuracy, with R2 values of 0.916 and 0.950 for AOY and BCE, respectively. The produced biodiesel complied with ASTM D6751 and EN 14214, showcasing its potential for renewable energy applications.

Characterization of activated carbon produced from the green algae Spirogyra used as a cost-effective adsorbent for enhanced removal of copper(ii): application in industrial wastewater treatment.

In this study, we prepared porous carbon (SPAC) derived from the green algae Spirogyra (SP), which was activated using natural lemon through pyrolysis at 600 °C for 3 h, and investigated its adsorption ability and performance towards copper ions in an aqueous solution. The physicochemical characteristics of SPAC were evaluated using FTIR, BET, SEM/EDS, XRD and pHPZC analyses and the results were compared with those of the raw algae (SP). The results indicated the presence of rich surface functional groups and that SPAC possessed a highly porous structure that increased the specific surface area by about 1.8 times compared to the SP surface (SBET = 71.087 m2 g-1 and VTotal = 12.019 cm3 g-1). XRD indicated that the main phase of the samples was CaCO3. The pHPZC value of activated carbon was 9.25. After optimizing the effects of operational parameters, the maximum adsorption efficiency of Cu2+ rapidly reached 95.09% after about 20 min of stirring time with an amount of 0.1 g adsorbent and an initial copper concentration of 200 mg L-1 at an optimum pH of around 5.28 and ambient temperature of 25 °C. The pseudo-first-order (PFO) nonlinear model provided a good description of the adsorption kinetics of SPAC. The experimental equilibrium data fit the Sips and Liu models slightly better than other isotherm models. The calculated thermodynamic parameters ΔH°, ΔS°, and ΔG° revealed that the adsorption process of Cu2+ was spontaneous and exothermic. Physisorption was the dominant mechanism for Cu2+ adsorption onto SPAC; SPAC was also evaluated for the adsorption of copper ions present in wastewater from the cable industry. Overall, the findings suggest that the prepared activated carbon can be employed as a cost-effective and promising adsorbent for the removal of toxic Cu2+ from wastewater.

HEAVY METALS TREATED SOIL EFFECTS ON THE CONCENTRATION OF CHLOROPHYLL A, B, AND MINERAL ELEMENTS IN ALGAE

Soil treated with different concentrations of copper (75, 160, and 190 mg/kg soil) and cadmium (4, 8, and 10 mg/kg soil) had assessments for their effects on the growth of algae (Cladophora and Spirogyra). Soil treated with copper (190 mg/kg) and cadmium (10 mg/kg) has shown a significant impact, decreasing the dry weight of Cladophora (1.600 and 0.353 mg) and Spirogyra (1.500 and 0.189 mg). Chlorophyll a and b content also expressed decreased with copper application to the soil at 190 mg/kg. Cladophora and Spirogyra algae had concentrations of 0.082 and 0.007 mg/g fresh weight, respectively. In algae Cladophora, the cadmium (10 mg/kg soil) levels reached 0.073 and 0.008 mg/g of fresh weight, while Spirogyra had concentrations of 0.013 and 0.011 mg/g. In the nutrient concentration status of cladophora, soil treatment with cadmium (10 mg/kg) was the most beneficial for phosphorus, chloride, and sodium levels (0.170, 0.010, and 0.010 mg/g, respectively). Similarly, the phosphorus and sodium concentrations had declined with copper treatments in algae spirogyra (0.150 and 0.040 mg/g, respectively), while chloride concentration reduction was by cadmium (10 mg/kg soil).

Testing the Efficiency of Silver Nanoparticles Manufactured Locally by the Alga Spirogyra in Inhibiting the Fungus Aspergillus flavus and Reduction of Aflatoxin B1

This experiment was conducted in the mycotoxins lab at the College of Agricultural Engineering Sciences-University of Baghdad with the aim of evaluating the effectiveness of bio- and locally manufactured silver nanoparticles by the alga Spirogyra locally and biologically manufactured silver nanoparticles in inhibiting the fungus Aspergillus flavus and reduction of aflatoxin B1. The results showed the alga Spirogyra highly efficient in the biologically manufactured silver nanoparticles and the size of the synthesized nanoparticles was 8.504 nm when examined by atomic force microscope AFM, which showed a high efficiency in inhibiting the isolate of the fungus Aspergillus flavus at concentrations 1.5, 2 and 3, and the percentage of inhibition was 86.7%, 97.64, 100%, respectively, It also indicated a high efficiency in preventing the fungus from producing aflatoxin B1 on the stored wheat grains. The concentrations of toxins in stored wheat samples were 6.25 ppb, 4.11 ppb and 0.0ppb for concentrations 1.5, 2, and 3 compared with the control treatment in which the concentration of aflatoxin B1 was 88.4ppb, as the percentage of reduction was 92.92%, 95.35% and 100, respectively. The results of biologically manufactured silver nanoparticles also showed an efficiency in reducing aflatoxin B1 from stored wheat grains. The concentration (3) was superior in reducing aflatoxin B1 to 2ppb compared to concentrations of (1.5 and 2), in which the toxin concentration reached 10.25 ppb and 7.15 ppb, respectively, with a reduction percentage of 88.4%, 91.91% and 97.73%.

Green biosynthesis, characterization of silver nanoparticles using a green alga Spirogyra sp., and their antioxidant and enzyme activities

A simple, environmentally friendly, inexpensive, and one-step alternative method was reported for the green biosynthesis of silver nanoparticles (AgNPs) operating the Spirogyra sp. extract as a reducing and stabilizing substance. Concentration of AgNO3 and reaction time were optimized to prepare AgNPs under controlled conditions. The synthesized silver nanoparticles were characterized by UV-Vis absorption spectroscopy, fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDX), and elemental mapping. The TEM analysis showed that the average particle size of AgNPs was 18.3 nm. Structural details of silver nanoparticles elucidated by Selected Area Electron Diffraction (SAED) based on TEM images. In addition, biological activity tests were applied to nanoparticles and algal extracts to determine antioxidant activity (3 different tests: DPPH (1,1-diphenyl-2-picrylhydrazil) radical scavenging activity, total phenolic content (TPC) and total flavonoid content (TFC)) and α-glucosidase enzyme inhibition. Antioxidant activity and α-glucosidase enzyme inhibition values of silver nanoparticles are higher than the values of Spirogyra sp. extracts.

Biodiesel Production from a Naturally Grown Green Algae Spirogyra Using Heterogeneous Catalyst: An Approach to RSM Optimization Technique

The present study focuses on oil extraction and biodiesel production from naturally grown green Spirogyra algae. Solvent oil extraction and oil expeller techniques were used to extract the Spirogyra algae oil (SALO), and the oil yields were compared to identify the most productive method. Using chicken eggshell waste (CESW) heterogeneous catalyst (HC) was prepared for the production of Spirogyra algae oil biodiesel (SALOBD). Furthermore, Box–Behnken (BB) assisted response surface method (RSM), an optimisation technique, was used in this study to achieve maximum algae biodiesel yield. From the 29 experimental trails, 96.18 % SALOBD was achieved at molar ratio (10:1), heterogeneous catalyst (0.6 wt.%), temperature (48 oC), and time (180 minutes). The predicted values of R2 (97.51%) and Adj. R2 (95.02 %) is found to be encouraging and fits well with the experimental values. The output results show that HC was identified as the significant process constraint followed by the time. The fatty acid composition (FAC) analysis by Gas Chromatography (GCMS) reveals the presence of 29.3 % unsaturated composition and 68.39 wt. % of the saturated composition. Finally, the important fuel properties of SALOBD were identified in accordance with ASTM D6751. The results obtained using chicken eggshell waste (CESW) for the production of biodiesel were recommended as a diesel fuel replacement to resist energy and environmental calamities.

Preparation and physicochemical properties of naturally grown green Spirogyra algae biodiesel

In this study, biodiesel was produced from a naturally grown green algae (Spirogyra). The algae were cultivated in an open pond for 180 days without any fertilizers or nutrients. The dried algae powder to oil yield and significant fuel properties of viscosity, density, cetane number, calorific value, flash point, pour, and cloud points are investigated for B10 to B100 blends. The results of solvent oil extraction show that at a 1:2 (algae powder to solvent) ratio and 65 ?C, algae oil yield was 22.66%. Furthermore, Box-Behnken assisted response surface optimization technique was implemented. From the 29 random experiments, 96.24% Spirogyra algae oil biodiesel (SAOBD) yield was achieved under the optimum conditions of 50 ?C, 180 minutes, the molar ratio of 9:1, and catalyst concentration of 0.5 wt%. The fatty acid composition reveals that 73.95 wt% saturated FAC was observed in SAOBD. The significant fuel properties are measured by following ASTM-D6751 standards, and 40% SAOBD in diesel fuel could be an optimum blend ratio for engine experimentation. Finally, regression equations with high correlation coefficients (R2) were developed to predict the various blend ratios for the fuel properties.

Zygospores of the green alga Spirogyra: new insights from structural and chemical imaging.

Zygnematophyceae, a class of streptophyte green algae and sister group to land plants (Embryophytes) live in aquatic to semi-terrestrial habitats. The transition from aquatic to terrestrial environments requires adaptations in the physiology of vegetative cells and in the structural properties of their cell walls. Sexual reproduction occurs in Zygnematophyceae by conjugation and results in the formation of zygospores, possessing unique multi-layered cell walls, which might have been crucial in terrestrialization. We investigated the structure and chemical composition of field sampled Spirogyra sp. zygospore cell walls by multiple microscopical and spectral imaging techniques: light microscopy, confocal laser scanning microscopy, transmission electron microscopy following high pressure freeze fixation/freeze substitution, Raman spectroscopy and atomic force microscopy. This comprehensive analysis allowed the detection of the subcellular organization and showed three main layers of the zygospore wall, termed endo-, meso- and exospore. The endo- and exospore are composed of polysaccharides with different ultrastructural appearance, whereas the electron dense middle layer contains aromatic compounds as further characterized by Raman spectroscopy. The possible chemical composition remains elusive, but algaenan or a sporopollenin-like material is suggested. Similar compounds with a non-hydrolysable character can be found in moss spores and pollen of higher plants, suggesting a protective function against desiccation stress and high irradiation. While the tripartite differentiation of the zygospore wall is well established in Zygnematopyhceae, Spirogyra showed cellulose fibrils arranged in a helicoidal pattern in the endo- and exospore. Initial incorporation of lipid bodies during early zygospore wall formation was also observed, suggesting a key role of lipids in zygospore wall synthesis. Multimodal imaging revealed that the cell wall of the sexually formed zygospores possess a highly complex internal structure as well as aromatics, likely acting as protective compounds and leading to impregnation. Both, the newly discovered special three-dimensional arrangement of microfibrils and the integration of highly resistant components in the cell wall are not found in the vegetative state. The variety of methods gave a comprehensive view on the intricate zygospore cell wall and its potential key role in the terrestrial colonization and plant evolution is discussed.

Synergistic Efficiency Between Types of Fungi and Algae for Wastewater Treatment

The study aims to demonstrate the efficiency of the synergy between types of fungi and algae for wastewater treatment. Samples are collected from the waters of Wadi al-Kharazi inside the University of Mosul. Four genera of organisms, two sexes of fungi, and two sexes of algae are used for the purpose of reacting.
 Examinations are conducted for water treated with fungi and algae, as 8 treatments are used compared to the control treatment that contains water alone. The pH function, bicarbonate ions, and sulfates with the two elements iron and copper are measured.
 The results of the bicarbonate examination show that the best biological treatment is in the mixed culturing of the alga Spirogyra maxima and the fungus Trichoderma asperallum. The average concentration during the incubation periods is 162.8 mg.l-1 compared to the average control treatment ranging 204.9 mg.l-1. The results of the sulfate examination show a decrease in concentration for all treatments compared to the control treatment. The best biological treatment in the mixed culturing is between the alga Spirogyra maxima and the fungus Mucor racemosus, as the removal rate reached 48% compared to the average of the control treatment. Examinations have demonstrated the synergy between fungi and algae in increasing the efficiency of pollutant removal rather than using both separately.

Biomineralization of ordered dolomite and magnesian calcite by the green alga Spirogyra

AbstractThe formation of ordered dolomite under Earth's surface conditions remains a challenge, although many researchers have now shown that microbes can facilitate the precipitation of this common mineral. This study provides the first evidence of dolomite biomineralization by the green alga Spirogyra (Zygnematales, Chlorophyta), a globally dispersed lacustrine genus. Microbial mats formed by Spirogyra occur in the hyperalkaline and ephemeral lake Caballo Alba, located in Central Spain and characterized by water solutions with high Mg/Ca ratios. Microscopic, geochemical, mineralogical and cytochemical studies have shown that accumulations of carbonates occur within different cells and locations of the alga. Biominerals mostly consist of single crystals of magnesian calcite and dolomite with variable proportions of Ca2+ and Mg2+. High‐resolution transmission electron microscopy and selected area electron diffraction patterns of the carbonates confirm the pervasive presence of super‐lattice reflections typical of ordered dolomite in compositions with greater than 32 mol% MgCO3. The curved surfaces of some carbonate crystals and their attachment to the organic surfaces represent imprints of a confined growth in compartments that act as a template for crystal nucleation and shape the crystals. Dyes reveal chemical differences in these compartments which explain the polymineral biomineralization and suggest that the alga do not strictly control the precipitation process. Zygnematales algae related with Spirogyra date back possibly to the Early Palaeozoic, thus suggesting that dolomite biomineralization could have been a common process through the Phanerozoic. This discovery provides new insight into the biotic formation of orderly dolomite and aids in the reconstructions of past lacustrine environments of dolomite deposition.

Optimization of Oil Yield from the Macro Algae Spirogyra by Solvent Extraction Process Using RSM and ANN

The present work was done to optimize the process parameters of the oil extraction from the algae species spirogyra by using n-hexane as the solvent using the Soxhlet apparatus. The response surface methodology (RSM) and artificial neural network (ANN) were employed to optimize the particle size of the algae powder, dryness level of the algae powder, solid to solvent ratio, reaction time, and extraction temperature of the oil extraction process. Also, the physiochemical properties of the extracted oil were investigated. The comparative evaluation was done between the RSM and ANN models to select the more precise and accurate model. The coefficient of determination, R 2 of 98.92%, and the mean absolute percentage deviation (MAPD) of 0.492% for ANN revealed that the current model created with a network topology of 3 : 11 : 1 with tansig (hyperbolic tangent sigmoid) transfer function in the input layer and purelin (pure linear) transfer function in the output layer trained with trainlm (Levenberg–Marquardt) algorithm found to provide the optimal solution with better accuracy in prediction of the output. The physicochemical properties investigated, such as heating value, flashpoint, density, viscosity, iodine number, acid value, saponification value, and cetane index, showed that the extracted oil from the algae spirogyra species can be used as an alternative fuel.

Biosorption of Boron from Industrial Wastewater by Green Algae Spirogyra sp.

Introduction: Increasing the concentration of Boron in drinking water, wastewater, and irrigation have negative effects on the human environment. This pollution can be partially removed by the application of phytoremediation technologies using algae or aquatic plants. The aim of the current study was to determine the biosorption capacity of the algae Spirogyra sp. for Boron from industrial wastewater and examine the best elimination conditions using different parameters.
 Materials and Methods: In this study, 100 g of fresh algal biomass was collected from the industrial wastewater of a copper mine located in Kerman, Iran.
 At first, algae was selected among various algal species concerning abundance and resistance ability to high concentrations of Boron. Then, removal of Boron by the algal was examined in terms of algae biomass levels (2 and 4 gr), incubation time intervals (2, 12. 24. 48, and 72 hours), and different concentrations of Boron (5, 10, 15, 25, and 100 ppm) on the were examined. The experiment was factorial with a completely randomized design framework and three replications.
 Results: The results presented that the elimination of Boron from industrial wastewater was performed by biomass of algae Spirogyra sp. The maximum Boron absorption was achieved at concentrations of 5 ppm and an incubation time of 12 hours. The absorption of Boron was higher in 4 gr than in 2 gr of algae biomass treatment.
 Conclusion: It can be concluded that algae Spirogyra sp. has a strong potential for boron removal in industrial wastewater containing boron ions.

Urban mosquitoes and filamentous green algae: their biomonitoring role in heavy metal pollution in open drainage channels in Nairobi industrial area, Kenya

BackgroundIndustrial wastewater is a human health hazard upon exposure. Aquatic organisms in contaminated wastewater may accumulate the toxic elements with time. Human population living in informal settlements in Nairobi industrial area risk exposure to such toxic elements. Biomonitoring using aquatic organisms in open drainage channels can be key in metal exposure assessment. Levels of Mercury (Hg), Lead (Pb), Chromium (Cr), Cadmium (Cd), Thallium (Tl), and Nickel (Ni) were established in samples of wastewater, filamentous green algae (Spirogyra) and mosquitoes obtained from open drainage channels in Nairobi industrial area, Kenya.ResultsPb, Cr, & Ni levels ranged from 3.08 to 15.31 µg/l while Tl, Hg, & Cd ranged from 0.05 to 0.12 µg/l in wastewater. The Pb, Cr, Ni, & Cd levels were above WHO, Kenya & US EPA limits for wastewater but Hg was not. Pb, Cr, Tl, & Ni levels in assorted field mosquitoes were 1.3–2.4 times higher than in assorted laboratory-reared mosquitoes. Hg & Cd concentrations in laboratory-reared mosquitoes (0.26 mg/kg & 1.8 mg/kg respectively) were higher than in field mosquitoes (0.048 mg/kg & 0.12 mg/kg respectively). The levels of Pb, Cr, & Ni were distinctively higher in field mosquito samples than in wastewater samples from the same site. Pb, Cr, Ni, Cd & Hg levels in green filamentous Spirogyra algae were 110.62, 29.75, 14.45, 0.44, & 0.057 mg/kg respectively. Correlation for Pb & Hg (r (2) = 0.957; P < 0.05); Cd & Cr (r (2) = 0.985; P < 0.05) in algae samples was noted. The metal concentrations in the samples analyzed were highest in filamentous green algae and least in wastewater.ConclusionWastewater, mosquitoes, and filamentous green algae from open drainage channels and immediate vicinity, in Nairobi industrial area (Kenya) contained Hg, Pb, Cr, Cd, Tl, and Ni. Mosquitoes in urban areas and filamentous green algae in open drainage channels can play a role of metal biomonitoring in wastewater. The potential of urban mosquitoes transferring heavy metals to human population from the contaminated wastewater should be investigated.

Biosorption of zinc from aqueous solution using algae and plant biomass

In the present study, the sorption capacity of plant biomass has been studied; particularly the ability of biomass algae Chlorella vulgaris, filamentous green algae Spirogyra sp. and roots, stems and leaves of an invasive plant Reynoutria japonica to bind up Zn2+ ions. The results of this biosorption study revealed that the rate and extent of uptake were affected by pH level, contact time and initial metal concentration. The maximum uptake of metal ions was obtained at pH 6.0. The equilibrium sorption data for metal system at pH 6 were described by the Langmuir isotherms model. For Zn2+, sorption capacity qmax of 17 mg/g was achieved using biomass from leaves. Removal of Zn2+ with 1g of biosorbent from leaves was almost 77% when present in low concentrations, whereas it is lower at higher concentrations.

Effects of seaweed ( Ulva lactuca ) and freshwater ( Spirogyra sp.) algae extracts on the salt tolerance of the bean ( Vicia faba L.)

Seed priming with algae extracts is a promising alternative to stimulate growth, development, and mitigate the harmful effects of salinity on plants. In the present study, we studied under a greenhouse, the effect of priming the seeds of bean (Vicia faba L.), with two concentrations (1% and 10%) of seaweed Ulva lactuca extract (SWE) and freshwater alga Spirogyra sp. extract, on some physiological and biochemical parameters of the bean, under four salinity levels (0, 2, 8, and 32 dS/m). The results indicated that the use of SWE and freshwater alga extract has no significant effect on proline content, total soluble sugars content, and electrolytes leakage, compared to untreated control, except for the salinity level S2 (8 dS/m) where the use of the freshwater alga extract at a concentration of 10% aggravated the leakage of electrolytes by 56% compared to the control. In non-saline condition, chlorophyll pigment content showed no significant variation between plants from treated and untreated seeds, but under the highest salinity level S3 (32 dS/m), the chlorophyll pigment content was significantly improved by the use of SWE and freshwater alga extract. Overall under saline conditions, the priming in algae extracts seemed to have a positive effect on bean, which could account, at least in part, for the enhanced chlorophyll pigments content. Novelty impact statement The effect of seed priming of the bean by two concentrations of seaweed (Ulva lactuca) and freshwater extracts was studied. Mitigating the effect of saline stress on the physiological and biochemical parameters of the bean was targeted. The saline stress of the bean on the chlorophyll b and total chlorophyll content was improved below the highest salinity level. The use of freshwater algae extracts with the same concentration aggravated the leakage of electrolytes.

Pyrolysis of the freshwater macroalgae Spirogyra crassa: Evaluating its bioenergy potential using kinetic triplet and thermodynamic parameters

The freshwater alga Spirogyra crassa was subjected to pyrolysis to investigate its potential use as a bioenergy feedstock. To do so, the pyrolysis behavior of the Spirogyra crassa under thermogravimetric scale was first determined at the temperature range from 25 to 800 °C, with three slow heating rates (5, 10, and 20 °C min−1) under an oxygen-free atmosphere. It is assumed that the pyrolysis of Spirogyra crassa occurs in four reaction steps with different kinetic triplets. The activation energy was obtained for each reaction step by concurrent use of four isoconversional methods (Friedman, Flynn-Wall-Ozawa, Kissinger-Akahira-Sunose, and Starink), with average values ranging from 120.6 to 217.0 kJ mol−1. Pre-exponential factors determined from the kinetic compensation effect were found to range between 6.88 × 107 and 7.54 × 1019 min−1. Master plot results indicated that the nth-order-based mechanisms described the pyrolysis behavior of organic matter and, subsequently, the pyrolysis behavior of inorganic matter follows Avrami-Erofeev nucleation mechanisms. According to the thermodynamics parameters, the pyrolysis of Spirogyra crassa verifies to be a non-spontaneous, endothermic, and complex conversion. The summative kinetic expression proposed from the estimated kinetic triplets is a satisfactory option for describing the pyrolysis kinetics of Spirogyra crassa, with a quality of adjustment above 93.3 %. In conclusion, the insights of this study confirm that Spirogyra crassa has considerable potential as a feedstock for bioenergy production, and could be used for engineering purposes in the design or simulation of large-scale pyrolysis reactors.

Effect of Anthropogenic Factors on the Ecosystem of the Yenisei River Anabranch within the City of Krasnoyarsk

In recent decades, freshwater ecosystems have regularly experienced blooms of green algae (green tides), causing environmental and economic damage. Blooms of green alga Spirogyra sp. occur in the ‘Abakanskaya’ anabranch of the Yenisei River in summer months. The anabranch is influenced by several anthropogenic factors: construction of a dam in the upper reaches; heated water discharge from a thermal power plant; fish farming. The aim of this study was to assess the impact of anthropogenic factors on the ecosystem of the Abakanskaya anabranch and to identify the main factors favoring Spirogyra sp. blooms. Samples were taken in May-September 2018-2019 at four sites: 1 – upstream of the dam (control), 2 – downstream of the dam, 3 – near the point of heated water discharge, 4 – downstream of the fish farm. Physical and chemical parameters, biomass and species composition of phytoplankton, phytoperiphyton, zooplankton, zoobenthos, and higher water plants, gross primary production (GPP), nitrogen content in biomass of periphyton, higher plants, and zoobenthos were studied. The main factor that caused changes in the community was that there was no water flow in the anabranch because of the low capacity of the dam drainage pipes. While upstream of the dam most ecosystem features were within the limits typical for this part of the Yenisei River, downstream of the dam, the system seemed to change from lotic to lentic: percentage of motile forms of phytoplankton, biomass of zooplankton, percentage of true zooplankton species, taxon number and taxonomic diversity of zooplankton and zoobenthos became higher; phytoperiphyton primary production rose (because of Spirogyra sp. bloom); higher water plants thrived. The other investigated factors, namely, thermal, nutrient, and organic pollution evidently produced combined effect on the ecosystem because of the absence of water flow, and their specific effects were not obvious

Filamentous green algae Spirogyra regulates methane emissions from eutrophic rivers.

Excessive growth of filamentous green algae in rivers has attracted much attention due to their functional importance to primary production and carbon cycling. However, comprehensive knowledge of how filamentous green algae affect carbon cycling, especially the CH4 emissions from river ecosystems, remains limited. In this study, incubation experiments were conducted to examine the factors regulating CH4 emissions from a eutrophic river with dense growth of filamentous green algae Spirogyra through combinations of biogeochemical, molecular biological, and stable carbon isotope analyses. Results showed that although water dissolved oxygen (DO) in the algae+sediment (A+S) incubation groups increased up to 19 mg L-1, average CH4 flux of the groups was 13.09 μmol m-2 day-1, nearly up to two times higher than that from sediments without algae (S groups). The significant increase of sediment CH4 oxidation potential and methanotroph abundances identified the enhancing sediment CH4 oxidation during Spirogyra bloom. However, the increased water CH4 concentration was consistent with depleted water [Formula: see text] and decreased apparent fractionation factor (αapp), suggesting the important contribution of Spirogyra to the oxic water CH4 production. It can thus be concluded that high DO concentration during the algal bloom promoted the CH4 consumption by enhancing sediment CH4 oxidation, while algal-linked oxic water CH4 production as a major component of water CH4 promoted the CH4 emissions from the river. Our study highlights the regulation of Spirogyra in aquatic CH4 fluxes and will help to estimate accurately CH4 emissions from eutrophic rivers with dense blooms of filamentous green algae. Graphical abstract.

Biosugar Production From Algae Spirogyra peipingensis by acid and enzymatic hydrolysis processes

Spirogyra peipingensis, green algae, is a suitable feedstock for biosugar production. This study analyzes biosugar production by the hydrolysis of S. peipingensis conducted by acid and enzymatic hydrolysis processes. Acid hydrolysis process was conducted by H2SO4 0,2 M acid with various concentrations (0,2,4,6,8, dan 10%). Enzymatic hydrolysis process was held by using amylase enzyme with vary concentrations (0,25,50,75,100 dan 125 KNU). The result showed that the hydrolysis process with H2SO4 acid generates higher sugar concentration than compared with the amylase enzyme. Enzymatic hydrolysis method produces the optimum sugar concentration which is made up 0,45 g/g in adding α-amylase enzyme 50 KNU. In contrast, hydrolysis acid process able to produce the optimum sugar concentration in 0,55 g/g in adding of H2SO4 10% 0,2 M acid.

Phytochemistry PREPARATION OF DIFFERENT CRUDE EXTRACT AND ANTIMICROBIAL STUDIES OF SPIROGYRA RHIZOPUS

Objective: The importance of this work is to prepare the crude extracts of Spirogyra rhizopus and to study the biological activity of crude extract against four bacterial strains.&#x0D; Materials and Methods: Spirogyra algae collected from Jimma town, and crude extracts were prepared by cold percolation method and sonication method and further analyzed for qualitative phytochemical analysis. The efficacy of crude extracts is tested for bacterial activity by disc-diffusion method.&#x0D; Results: The maximum zone of inhibition shown by the crude extract is compared to standard and control. Among the four extracts, chloroform extract displayed the promising inhibitory action against four bacterial strains.&#x0D; Conclusions: The preliminary study concludes that green algae S. rhizopus is a potential source of pharmacologically active lead molecules. In vitro screening of crude extracts of green algae S. rhizopus shows promising activity against bacterial strains and thus suggests its application in drug discovery research.