scholarly journals Bioflocculation of Euglena gracilis via direct application of fungal filaments: a rapid harvesting method

Author(s):  
Danielle Bansfield ◽  
Kristian Spilling ◽  
Anna Mikola ◽  
Jonna Piiparinen

AbstractThe high cost and environmental impact of traditional microalgal harvesting methods limit commercialization of microalgal biomass. Fungal bioflocculation of microalgae is a promising low-cost, eco-friendly method but the range of fungal and microalgal species tested to date is narrow. Here, eight non-pathogenic, filamentous fungi were screened for their ability to self-pelletize and flocculate Euglena gracilis (ca.50 µm motile microalga) in suspension. Self-pelletization was tested under various rotational speeds, and species which formed pellets (Ø > 0.5 cm) were selected for harvesting tests. Filaments of each species were combined with E. gracilis at various ratios based on dry weight. Harvesting efficiency was determined by measuring the change in cell counts over time, and settling of the flocs was evaluated by batch settling tests. Three fungal species, Ganoderma lucidum, Pleurotus ostreatus, and Penicillium restrictum, were able to reliably flocculate and harvest 62–75% of the microalgae while leaving it unharmed. The results demonstrated that self-pelletization, harvesting, and settling were dependent on the fungal species. The fungi to algae ratio also had significant but contrasting effects on harvesting and settling. In balancing the needs to both harvest and settle the biomass, the optimal fungi to algae ratio was 1:2. The application of fungal filaments to microalgae in suspension produced readily settling flocs and was less time-consuming than other commonly used methods. This method is especially attractive for harvesting microalgal biomass for low-value products where speed, low cost, and cell integrity is vital.

Author(s):  
Kavitha. K ◽  
Shankari. K ◽  
Meenambiga S. S

Lipase enzyme which catalyses the hydrolysis of fats performs a variety of chemical reactions including esterification, trans-esterification, acidolysis and aminolysis. Lipases are widely used for biotechnological application in dairy industry, oil processing and production of surfactants and preparation of enatiomerically pure pharmaceuticals. Lipases are extracted from plants, animals and microorganisms whereas high amount of lipases are produced by microbes when compared to plants and animal source. Fungi serve as a major source in the production of industrial lipase. Fungi play a vital role in removing hazardous compounds formed by crude oil contamination from oil spill during lipase extraction. Aspergillus flavus, Aspergillus niger, Penicillium restrictum, Rhizomucar rhizopodiformis, Rhizopus oligosporous, Candida rugosa, Rhizopus oryzae, Fusarium oxysporum are few fungal species involved in the production of lipase. Among the species, Aspergillus species produce efficient amount of lipase. Lipase extracted from fungi is more stable and have more diverse properties compared to lipase from other source. Fungal lipases stand out as major source because of their catalytic activity, low cost of production and relative ease in genetic manipulation. This review focuses on the various methods of lipase extraction from Aspergillus species and its applications.


2020 ◽  
Vol 11 (1) ◽  
pp. 174
Author(s):  
Konstantinos P. Papadopoulos ◽  
Christina N. Economou ◽  
Athanasia G. Tekerlekopoulou ◽  
Dimitris V. Vayenas

Algal/cyanobacterial biofilm photobioreactors provide an alternative technology to conventional photosynthetic systems for wastewater treatment based on high biomass production and easy biomass harvesting at low cost. This study introduces a novel cyanobacteria-based biofilm photobioreactor and assesses its performance in post-treatment of brewery wastewater and biomass production. Two different supporting materials (glass/polyurethane) were tested to investigate the effect of surface hydrophobicity on biomass attachment and overall reactor performance. The reactor exhibited high removal efficiency (over 65%) of the wastewater’s pollutants (chemical oxygen demand, nitrate, nitrite, ammonium, orthophosphate, and total Kjeldahl nitrogen), while biomass per reactor surface reached 13.1 and 12.8 g·m−2 corresponding to 406 and 392 mg·L−1 for glass and polyurethane, respectively, after 15 days of cultivation. The hydrophilic glass surface favored initial biomass adhesion, although eventually both materials yielded complete biomass attachment, highlighting that cell-to-cell interactions are the dominant adhesion mechanism in mature biofilms. It was also found that the biofilm accumulated up to 61% of its dry weight in carbohydrates at the end of cultivation, thus making the produced biomass a suitable feedstock for bioethanol production.


HortScience ◽  
2022 ◽  
Vol 57 (1) ◽  
pp. 32-39
Author(s):  
Dharti Thakulla ◽  
Bruce L. Dunn ◽  
Carla Goad ◽  
Bizhen Hu

Algae is not desirable in hydroponics and creates problems such as reduced yield and decreased dissolved oxygen, and affects the physiology of plants and, thus, needs to be controlled. An experiment was conducted in Ebb and Flow hydroponic systems to investigate the application timing and rates of two hydrogen peroxide products (Zerotol and PERpose Plus). Treatments included 35 mL weekly, 35 mL biweekly, 70 mL weekly, 70 mL biweekly, and a control with no application of hydrogen peroxide using a 40-gallon reservoir of water. Pepper ‘Early Jalapeno’ and ‘Lunchbox Red’ and tomato ‘Geronimo’ and ‘Little Sicily’ were used. The study was conducted in a split-plot design with two replications over time. Plant growth parameters, including plant height, flower number, net CO2 assimilation, fresh weight, and dry weight were recorded. Algae data, including dry weight, algae cell counts, and chl a were also measured. Results indicated that with increasing rate and timing of either product decreased algae counts, dry weight, and chl a values. However, weekly and biweekly application of 70 mL of both products were not different for algae quantification. In pepper, plant height, shoot fresh and dry weight, and root fresh and dry weight were found to be significantly greater with Zerotol 35 mL biweekly, Zerotol 70 mL weekly, PERpose Plus 35 mL biweekly, and PERpose Plus 70 mL weekly compared with the control. ‘Lunchbox Red’ was significantly greater than ‘Early Jalapeno’ in all growth parameters, except soil plant analysis development (SPAD). ‘Lunchbox Red’ had the greatest flower number, with weekly application of 70 mL PERpose Plus. In tomato, greatest flower number and SPAD were observed in ‘Geronimo’ with a weekly application of 70 mL PERpose Plus and 70 mL Zerotol, respectively. Greater shoot and root fresh and dry weight for both tomato cultivars were recorded with 35 mL biweekly or 70 mL weekly application with either product. The results from both plants as well as algae analysis suggest that weekly application of 70 mL of either Zerotol or PERpose Plus produced the best results in terms of controlling algae and improving the growth of pepper and tomato plants.


2008 ◽  
Vol 58 (6) ◽  
pp. 1193-1198 ◽  
Author(s):  
S. Vinitnantharat ◽  
W. Chartthe ◽  
A. Pinisakul

Textile wastewater normally has a visible color although it has low concentration. This may affect the aquatic ecosystem. Two dyestuffs, Reactive Red 141 (RR141) and Basic Red14 (BR14) were used as compound models. RR 141 is an anionic dye which has a big molecule whereas BR 14 is a cationic dye and has a small molecule. The target organisms for toxicity test were green algae (Chlorella sp.) and waterfleas (Moina macrocopa). The effect of humic acid on the toxicity of dyestuffs to test organisms was also investigated. From the observation of cell counts, Chlorophyll a and dry weight of algae in the dye solutions for 4 days, it was found that all parameters increased as times increased. This revealed that algae could utilize dyestuffs as a carbon source. However, BR14 gave higher absorbance than RR141 at the wavelength of 430 nm which competed to the Chlorophyll a for algal photosynthesis. This resulted in the 96-h EC50 of BR14 and RR141 to Chlorella sp. were 10.88 and 95.55 mg/L, respectively. As for dye toxicity to waterfleas, the 48-h LC50 of BR14 and RR141 to waterfleas were 4.91 and 18.26 mg/L, respectively. The high toxicity of BR14 to waterfleas related to the small molecule of dye could pass into the cell and was absorbed by organelles of waterfleas. Toxicity of BR14 in humic acid solution to Chlorella sp. showed less toxic than RR141 in humic acid solution. This dues to the negative charge of humic acid could bound with a positive charge of BR14, resulted in low amount of BR14 remaining in the bulk solution. The toxicity of BR14 and RR141 in humic acid solution to waterfleas was increased as humic acid increased. Hence, the proper treatment of textile wastewater to yield low concentration of dyes in the effluent before discharging to the natural water is needed.


2019 ◽  
Vol 7 (12) ◽  
pp. 670 ◽  
Author(s):  
Teresa Lopes da Silva ◽  
Patrícia Moniz ◽  
Carla Silva ◽  
Alberto Reis

Microbial oils have been considered a renewable feedstock for bioenergy not competing with food crops for arable land, freshwater and biodiverse natural landscapes. Microalgal oils may also have other purposes (niche markets) besides biofuels production such as pharmaceutical, nutraceutical, cosmetic and food industries. The polyunsaturated fatty acids (PUFAs) obtained from oleaginous microalgae show benefits over other PUFAs sources such as fish oils, being odorless, and non-dependent on fish stocks. Heterotrophic microalgae can use low-cost substrates such as organic wastes/residues containing carbon, simultaneously producing PUFAs together with other lipids that can be further converted into bioenergy, for combined heat and power (CHP), or liquid biofuels, to be integrated in the transportation system. This review analyses the different strategies that have been recently used to cultivate and further process heterotrophic microalgae for lipids, with emphasis on omega-3 rich compounds. It also highlights the importance of studying an integrated process approach based on the use of low-cost substrates associated to the microalgal biomass biorefinery, identifying the best sustainability methodology to be applied to the whole integrated system.


Author(s):  
Mercedes Roca-Espiau ◽  
Marcio Andrade-Campos ◽  
Jorge J. Cebolla ◽  
Laura López de Frutos ◽  
Blanca Medrano-Engay ◽  
...  

Abstract Background Chronic fatigue (CFg) is a prevalent symptom in Gaucher disease (GD) at diagnosis (79%) and remains in a quarter of patients after years of therapy. Bone abnormalities are present in over 70% and peripheral neuropathy in about 11% of the patients, which contributes to the disabling and debilitating complications. Our hypothesis is that other factors such as muscle-tendinous weakness could have influence in the development of CFg. Methods We have evaluated the fiber structure and elasticity of muscle-tendinous unit by strain-elastography (S-ELA) and analyzed their influence in the CFg. S-ELA study was performed in Achilles tendon in 25 type 1 and two type 3 GD patients, all of them with fatigue and were on enzymatic replacement therapy for mean 13 years; simultaneously, bone marrow burden by MRI and calcaneus ultrasound densitometry were evaluated. Blood cell counts, plasma biomarkers, GBA1 genotyping, and SF36 quality of life scale (QoL) were also performed. Statistical analysis: descriptive and comparative test. Results All patients showed a normal Achilles tendinous structure. Abnormal stiff grade 2–3 was found in 17/27 (62.9%); in 11/27 (40.7%) of patients, the alteration was bilateral. There were no correlations between the S-ELA results to other variables; nevertheless, a significant correlation between the degree of tendon hardness and the low score on the QoL scales (p = 0.0035) was found. The S-ELA is a sensitive painless, fast, and low cost method to detect muscle-tendinous subclinical dysfunction that could contribute to CFg in GD. The identification of subclinical tendon alteration would be a sign of alarm, focused on the risk of development of bone complications. Conclusion Intratendinous alteration in strain-elastography is an independent variable in GD patients with persistent fatigue.


2020 ◽  
Vol 12 (21) ◽  
pp. 9158
Author(s):  
Xiaomiao Tan ◽  
Jiangyu Zhu ◽  
Minato Wakisaka

The development of efficient, environmentally friendly, low-cost approaches used to boost the growth of microalgae is urgently required to meet the increasing demands for food supplements, cosmetics, and biofuels. In this study, the growth promotion effects of protocatechuic acid (PCA) in the freshwater microalga Euglena gracilis were confirmed for the first time. PCA is a simple phenolic compound derived from natural plants and has a range of biological functions. The highest biomass yield, 3.1-fold higher than that of the control, used at 1.3 g·L−1, was obtained at 800 mg·L−1 of PCA. The yields of the metabolites chlorophyll a, carotenoids, and paramylon in the presence of PCA at 800 mg·L−1 were 3.1, 3.3, and 1.7 times higher than those of the control group, respectively. The highest paramylon yield was achieved at a lower dosage of PCA (100 mg·L−1), which is considered to be feasible for economic paramylon production. The growth and biosynthesis of metabolites stimulated by phytochemicals such as PCA could be an efficient and cost-effective strategy to enhance the productivity of microalgae in large-scale cultivations.


2020 ◽  
Vol 6 (3) ◽  
pp. 172 ◽  
Author(s):  
Guirong Tang ◽  
Yanfang Shang ◽  
Shiqing Li ◽  
Chengshu Wang

The Woronin body (WB) is a peroxisome-derived dense-core vesicle, a self-assembling hexagonal crystal of a single protein Hex1. This organelle is specific to the ascomycete fungi belonging to the Pezizomycotina subphylum by functioning in sealing septal pores in response to mycelium damage and the control of cell heterogeneity. We retrieved all available Hex1-domain containing proteins of different fungi from the GenBank database and found considerable length variations among 460 obtained Hex1 proteins. However, a highly conserved Hex1 domain containing 75 amino acid residues with a specific S/A-R/S-L consensus motif for targeting peroxisome is present at the carboxy-terminus of each protein. A homologous Hex1 gene, named MrHex1, was deleted in the entomopathogenic fungus Metarhizium robertsii. It was found that MrHex1 was responsible for WB formation in M. robertsii and involved in sealing septal pores to maintain cell integrity and heterogeneity. Different assays indicated that, relative to the wild-type (WT) strain, ∆Mrhex1 demonstrated a growth defect on a solid medium and substantial reductions of conidiation, appressorium formation and topical infectivity against insect hosts. However, there was no obvious virulence difference between WT and mutants during injection of insects. We also found that ∆MrHex1 could tolerate different stress conditions like the WT and the gene-rescued mutant of M. robertsii, which is in contrast to the reports of the stress-response defects of the Hex1 null mutants of other fungal species. In addition to revealing the phenotypic/functional alterations of the Hex1 deletion mutants between different pathotype fungi, the results of this study may benefit the understanding of the evolution and WB-control of fungal entomopathogenicity.


2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Tadashi Toyama ◽  
Tsubasa Hanaoka ◽  
Koji Yamada ◽  
Kengo Suzuki ◽  
Yasuhiro Tanaka ◽  
...  

Abstract Background Euglena gracilis, a unicellular flagellated microalga, is regarded as one of the most promising species as microalgal feedstock for biofuels. Its lipids (mainly wax esters) are suitable for biodiesel and jet fuel. Culture of E. gracilis using wastewater effluent will improve the economics of E. gracilis biofuel production. Enhancement of the productivity of E. gracilis biomass is critical to creating a highly efficient biofuels production system. Certain bacteria have been found to promote microalgal growth by creating a favorable microenvironment. These bacteria have been characterized as microalgae growth-promoting bacteria (MGPB). Co-culture of microalgae with MGPB might offer an effective strategy to enhance microalgal biomass production in wastewater effluent culture systems. However, no MGPB has been identified to enhance the growth of E. gracilis. The objectives of this study were, therefore, to isolate and characterize the MGPB effective for E. gracilis and to demonstrate that the isolated MGPB indeed enhances the production of biomass and lipids by E. gracilis in wastewater effluent culture system. Results A bacterium, Emticicia sp. EG3, which is capable of promoting the growth of microalga E. gracilis, was isolated from an E. gracilis-municipal wastewater effluent culture. Biomass production rate of E. gracilis was enhanced 3.5-fold and 3.1-fold by EG3 in the co-culture system using a medium of heat-sterilized and non-sterilized wastewater effluent, respectively, compared to growth in the same effluent culture but without EG3. Two-step culture system was examined as follows: E. gracilis was cultured with or without EG3 in wastewater effluent in the first step and was further grown in wastewater effluent in the second step. Production yields of biomass and lipids by E. gracilis were enhanced 3.2-fold and 2.9-fold, respectively, in the second step of the system in which E. gracilis was co-cultured with EG3 in the first step. Conclusion Emticicia sp. EG3 is the first MGPB for E. gracilis. Growth-promoting bacteria such as EG3 will be promising agents for enhancing E. gracilis biomass/biofuel productivities.


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