Bioremediation Capacity of Edaphic Cyanobacteria Nostoc linckia for Chromium in Association with Other Heavy-Metals-Contaminated Soils

Anthropogenic activity is the main factor contributing to soil pollution with various toxic metals, including Cr(VI), which dictates the need for decontamination. Often, the traditionally used remediation methods (soil removal, stabilization/solidification, physicochemical extraction, and soil washing) are not sufficiently efficient. Among gentle soil remediation, options can be considered. The aim of this study is to assess the ability of Nostoc linckia to remediate soils contaminated with Cr(VI) in association with other metals. Metal uptake by biomass was assessed using neutron activation analysis, while the components of Nostoc biomass were determined using specific methods. The capacity to accumulate chromium from the contaminated environment (Cr in association with Fe, Ni, Cu, and Zn) by the Nostoc linckia is kept at a high level for three generations of cyanobacterium, and the capacity to accumulate Fe, Ni, Cu, and Zn is growing over the cultivation cycles. The process of accumulation of heavy metals is associated with significant changes in the biochemical composition of Nostoc biomass. Due to the high bioaccumulation capacity and the specific growth mode with the formation of crusts on the soil surface, the edaphic cyanobacteria Nostoc linckia is an important candidate for the bioremediation of soil contaminated with chromium in association with other metals.

Potential Antioxidant and Anticancer Activities of Secondary Metabolites of Nostoc linckia Cultivated under Zn and Cu Stress Conditions

The objective of the present study is to determine the antioxidant and anticancer activities of Nostoc linckia extracts cultivated under heavy metal stress conditions (0.44, 0.88, and 1.76 mg/L for zinc and 0.158, 0.316, 0.632 mg/L for copper). Phycobiliprotein, phenolic compounds, flavonoids, and tannins were measured. Active ingredients of extracts were evaluated by GC-mass spectroscopy. The obtained results revealed that higher zinc and copper concentrations showed growth inhibition while 0.22 mg/L (Zn) and 0.079 mg/L (Cu) enhanced growth, reaching its maximum on the 25th day. Increases in catalase, lipids peroxidation, and antioxidants, as well as tannins and flavonoids, have been induced by integration of 0.88 mg/L (Zn) and 0.316 mg/L (Cu). Elevation of Zn concentration induced augmentation of antioxidant activity of crude extract (DPPH or ABTS), with superior activity at 0.44 mg/L zinc concentration (81.22%). The anticancer activity of Nostoc linckia extract (0.44 mg/L Zn) tested against four cancer cell lines: A549, Hela, HCT 116, and MCF-7. The extract at 500 µg/mL appeared the lowest cell viability of tested cell lines. The promising extract (0.44 mg/L Zn) recorded the lowest cell viability of 25.57% in cervical cell line, 29.74% in breast cell line, 33.10% in lung cell line and 34.53% in the colon cell line. The antioxidant active extract showed significant stability against pH with attributed increase in antioxidant activity in the range between 8–12. The extract can be used effectively as a natural antioxidant and anticancer after progressive testing.

Biological Controls of Fusarium Tomato-wilt Disease by the Blue-green Alga Nostoc Spp.

This study investigates the effect of extract and culture of certain cyanobacteria on pathogenic Fusarium oxysporum f. sp. lycopersici (FOL) that infects tomato (Solanum lycopersicum) plant in vitro and in vivo. Some cyanobacteria isolates were isolated from saline soils of El-Hamoul and Seidy Salem location and identified. Bioactive compounds of isolates were analyzed by GC–MC. Dry weight, carotene, chlorophyll content, and total phenolic compounds of isolates were measured. Plant height (cm), dry weight (g), fruit number, and fruit weight (g) of tomato were estimated. Isolates were defined as Nostoc calcicola and Nostoc linckia. GC/MS analysis showed 49 and 35 bioactive compounds from N. calcicola and N. linckia, respectively. N. calcicola possess a higher amount of dry weight, chlorophyll a, carotenoid, and total phenol that measured 670.43 mg.L− 1, 1.91 mg/g fresh wt., 466.67 µg/g fresh wt., and 47.00 mg (GAE) g− 1, respectively, compared to N. linckia. After 100 days, the results showed highest yield values of tomato fruits with Nostoc sp. compared with untreated plants and plants infected with Fusarium.

The participation of cyanobacteria in reducing the concentration of fusariotoxins and heavy metal ions in aqueous solutions (model experiments)

Aim. The goal was to establish the effect of soil cyanobacteria (CB) Fischerella muscicola, Nostoc paludosum and Nostoc linckia on change in the concentration of heavy metal ions (HM) and fusariotoxins in aqueous media.Material and Methods. In order to plot the kinetics of sorption by dry biomass of CB Fischerella muscicola and Nostoc paludosum of copper(II), lead(II) and cadmium ions from solutions with a concentration of 10‐4mol/L, the method of potentiometry with ion‐selective electrodes was used. The concentration of fusariotoxins in the filtrate of the contact medium of Fischerella muscicola CB and Nostoc linckia with F. culmorumwas determined by HPLC.Results. The kinetics of sorption of TM ions by dry biomass of the CB isbest described by a modified second‐order model. According to the model, the sorption process limits the ion exchange reaction. In the presence of CB Fischerella muscicola and Nostoc linckia with a titer of 1.8∙106 cells/mL (1:100 dilution), a decrease in toxin and lycomarasmin in T‐2 medium occurs. However, this increases the concentration of fusaric acid and deoxynivalenol. In the variant where the titer of CB is equal to 1.8∙107cells/mL, the concentration of lycomarasmin is significantly reduced, while there is no change in the concentration of other fusariotoxins.Conclusion. Dry biomass of CB, having a high bisorption potential, can act as a good biosorbent with respect to copper(II), lead(II) and cadmium ions. A decrease in the concentration of fusariotoxins indicates the possibility of isolating active CB substances that can inhibit the biosynthesis of certain toxins of micromycetes of the genus Fusarium, reducing both the phytotoxicity of plant growth media and increasing the safety of crop production.

Obtaining phycobiliprotein-containing Nostoc linckia (Roth.) Born. et Flah biomass via bioconversation of waste water from reticulating aquaculture systems (RAS)

The paper studies the possibility of bioconversion of waste water from recirculating aquaculture systems (RAS). For this purpose, cyanobacteria Nostoc linckia (Roth.) Born. et Flah. was grown on waste water from RAS. In the process of cultivation, indicators of total mineralization, pH, and culture density were monitored. In the waste water, the content of various forms of nitrogen (NH4+, NO3-, NO2-), the content of P and S before and after the growth of cyanobacteria were determined It was noted that as a result of growing N. linckia in RAS waste water, a decrease in the content of various forms of nitrogen, sulfur and phosphorus is observed. Also, the content of phosphates decreased from 35×10-3 to 5×10-3 mg.L-1 and the content of sulfates from 95×10-3 to 25×10-3 mg.L-1. Moreover, the resulting biomass of cyanobacteria contained 57 % of proteins, 20 % of lipids and 11% of carbohydrates. It was found that N. linckia biomass is a promising source of phycobiliprotein pigments: phycocyanin, allophycocyanin and phycoerythrin.