Assessment of Nutrients Recovery Capacity and Biomass Growth of Four Microalgae Species in Anaerobic Digestion Effluent

Four microalgae species were evaluated for their bioremediation capacity of anaerobic digestion effluent (ADE) rich in ammonium nitrogen, derived from a biogas plant. Chlorella vulgaris, Chlorella sorokiniana, Desmodesmus communis and Stichococcus sp. were examined for their nutrient assimilation efficiency, biomass production and composition through their cultivation in 3.7% v/v ADE; their performance was compared with standard cultivation media which consisted in different nitrogen sources, i.e., BG-11NO3 and BG-11ΝΗ4 where N-NO3 was replaced by N-NH4. The results justified ammonium as the most preferable source of nitrogen for microalgae growth. Although Stichococcus sp. outperformed the other 3 species in N-NH4 removal efficiency both in BG-11NH4 and in 3.7% ADE (reaching up to 90.79% and 69.69% respectively), it exhibited a moderate biomass production when it was cultivated in diluted ADE corresponding to 0.59 g/L, compared to 0.89 g/L recorded by C. vulgaris and 0.7 g/L by C. sorokiniana and D. communis. Phosphorus contained in the effluent and in the control media was successfully consumed by all of the species, although its removal rate was found to be affected by the type of nitrogen source used and the particular microalgae species. The use of ADE as cultivation medium resulted in a significant increase in carbohydrates content in all investigated species.

Analysis of the ecological condition of water and bottom substrates of the lower Dniester by the method of biotesting on microalgae

In the autumn-spring periods 2018 - 2020. biotesting of water and bottom sediments of the lower Dniester and Ukrainian coastal waters of the Dniester region of the Black Sea was carried out by biotesting on a laboratory culture of planktonic algae Desmodesmus communis. The assessment of the ecological and toxicological situation and a comparative analysis of indicators of the level of pollution of the ecosystem of the “lower reaches of the Dniester” testify to the chronic pollution of this ecosystem by dangerous toxicants, acute toxicity occurs only during peak periods, while chronic toxicity is constantly manifested. It was found that in the overwhelming majority of water areas with different nature of anthropogenic factors and anthropogenic load, there were no toxic substances. Hazardous pollutants were more often found in the surface water layer of the zones affected by urban wastewaters on the Ukrainian coast of the Dniester region of the Black Sea.

Desmodesmus communis (E.Hegewald) E.Hegewald Mikroalginin Kültürü ve Biyokimyasal Özellikleri

In this study, culture medium and growth conditions were detected for Desmodesmus communis (E. Hegewald) E. Hegewald (Sphaeropleales) with KF470792 Accession Number that isolated from Thrace inland water (Bahçedere Stream, Tekirdağ, Turkey) and determined by molecular taxonomy techniques. The microalgae was cultured under detected conditions (nutrients, pH, temperature, light density and aeration) and when the culture was reached to stationary phase microalgae biomass was harvested for biochemical analysis. Total protein, total lipid, fatty acid and amino acid compositions, vitamin E amounts and variety were detected. Cell density was 9.76x105 colony/ml; dry biomass was 0.762 g/l; chlorophyll-a was 13.3 mg/l in BG11 culture medium (7.5 pH, 24±2ºC, 500 ml/min. aeration). According to biochemical analysis; total protein amount was 42.59% (dw/w); total lipid amount was 5.23% (dw/w) and vitamin E amount was 3694.24 µg/glipid. The most abundant fatty acid was linolenic acid (35.18%); amino acid was glutamic acid (46.9 mg/g).

Guanicid and PHMG Toxicity Tests on Aquatic Organisms

The emergence and development of new algicidal products is caused by the ever increasing popularity of garden ponds as well as the use of these products in the fisheries sector, especially for disposal of cyanobacteria and algae. Most frequent means of combating cyanobacteria and algae are applications of algicidal substances. Newly developed algaecides include Guanicid and polyhexamethylene guanidine hydrochloride (PHMG). The aim of the study was to identify toxic effects of Guanicid and PHMG on zebrafish (Danio rerio) and green algae (Desmodesmus communis). We determined the acute toxicity in fish according to ČSN EN ISO 7346-1, and conducted the freshwater algae growth inhibition test according to ČSN ISO 8692 methodology. For inhibition tests with green algae we chose Guanicid and PHMG concentrations of 0.001, 0.005, and 0.010 ml/L. For fish short-term acute toxicity tests we chose Guanicid concentrations of 0.010, 0.050, 0.150, 0.200, 0.250, and 0.300 ml/L and PHMG concentrations of 0.010, 0.025, 0.050, 0.075, 0.100, and 0.125 ml/L. In case of zebrafish (Danio rerio), the LC50 value for Guanicid is 0.086 ml/L, while the LC50 value for PHMG is 0.043 ml/L. Effects of Guanicid on inhibition of green algae (Desmodesmus communis) appear highly significant (p < 0.010) at a concentration of 0.010 ml/L. For PHMG, these effects are highly significant (p < 0.001) at concentrations of 0.005 and 0.010 ml/L in 48 hours.

Water quality assessment in a shallow lake used for tourism

The routine evaluation of water quality is limited to lakes with the largest area. In Poland, only lakes with an area exceeding 50 hectares are monitored by the State Environmental Monitoring System. For many local communities, however, small lakes are more important. This applies mainly to areas with a small number of lakes, where even the smallest lakes are used for various purposes. This paper presents the results of phytoplankton analysis in a small and shallow lake used for recreation. The study was conducted at three sites located in different parts of the lake. A total of 122 algae taxa were identified in the phytoplankton, mainly diatoms and green algae. The most constant taxa in the lake were: Stephanodiscus hantzschii, Desmodesmus communis, Pediastrum tetras and Crucigenia tetrapedia. The average phytoplankton biomass was 37 mg l−1. The maximum biomass, almost 140 mg dm−3, was recorded in late July at the site located near the beach. At that time, there was a massive cyanobacterial bloom composed of Microcystis wesenbergii and Aphanizomenon issatschenkoi. Based on these studies, the lake should be classified as hypertrophic with bad ecological status. This lake should not be used for recreational purposes in the current state.