Gergely Maróti
56408420600
Publications - 11
Cyanobacteria-Fungi Co-Cultures: Which Partner Contributes to Antifungal Activity?
Publication Name: Current Microbiology
Publication Date: 2024-11-01
Volume: 81
Issue: 11
Page Range: Unknown
Description:
Cyanobacteria synthesize secondary metabolites with antifungal activity, making them potential biopesticide agents for sustainable, eco-friendly agriculture. Programmes to identify Cyanobacterial strains with effective bioactivity generally screen strains maintained in culture collections. These strains are often monoclonal but non-axenic and this may potentially influence the bioactivity of the generated biomass. The present study investigated in vitro antifungal activity of Nostoc muscorum MACC-189 and N. linckia MACC-612 strains co-isolated with fungal co-partners and maintained in the Mosonmagyaróvár Algal Culture Collection (MACC). The fungal co-partners were isolated from the Cyanobacterial stock cultures and identified as Purpureocillium lilacinum and Sarocladium sp., respectively. The cultures were tested against seven phytopathogens. The phytopathogenic fungi were grown on potato dextrose agar plates and suspension cultures of the Cyanobacteria-fungi and isolated fungal co-partners were placed in the centre of the plate. Antifungal effects were assessed semi-quantitatively after 10 days of incubation. The Cyanobacteria-fungal co-cultures had antifungal activity against Monilinia fructigena and Aspergillus sp. with the N. muscorum/P. lilacinum culture being the most effective. The fungal isolates inhibited M. fructigena with P. lilacinum having a dose-dependent response but did not inhibit Aspergillus sp. This suggested that the antifungal effect of the Cyanobacterial cultures on M. fructigena was due to the fungal partner rather than the cyanobacterium while the antifungal effect on Aspergillus sp. was due to the cyanobacterium partner. As it was not possible to maintain living axenic N. muscorum and N. linckia cultures, this could not be conclusively confirmed. These results highlight the importance of either using axenic cultures or identifying the co-isolates when testing Cyanobacteria cultures for antifungal bioactivity.
Open Access: Yes
Comparison of plant biostimulating properties of Chlorella sorokiniana biomass produced in batch and semi-continuous systems supplemented with pig manure or acetate
Publication Name: Journal of Biotechnology
Publication Date: 2024-02-10
Volume: 381
Issue: Unknown
Page Range: 27-35
Description:
Microalgae-derived biostimulants provide an eco-friendly biotechnology for improving crop productivity. The strategy of circular economy includes reducing biomass production costs of new and robust microalgae strains grown in nutrient-rich wastewater and mixotrophic culture where media is enriched with organic carbon. In this study, Chlorella sorokiniana was grown in 100 l bioreactors under sub-optimal conditions in a greenhouse. A combination of batch and semi-continuous cultivation was used to investigate the growth, plant hormone and biostimulating effect of biomass grown in diluted pig manure and in nutrient medium supplemented with Na-acetate. C. sorokiniana tolerated the low light (sum of PAR 0.99 ± 0.18 mol/photons/(m2/day)) and temperature (3.7–23.7° C) conditions to maintain a positive growth rate and daily biomass productivity (up to 149 mg/l/day and 69 mg/l/day dry matter production in pig manure and Na-acetate supplemented cultures respectively). The protein and lipid content was significantly higher in the biomass generated in batch culture and dilute pig manure (1.4x higher protein and 2x higher lipid) compared to the Na-acetate enriched culture. Auxins indole-3-acetic acid (IAA) and 2-oxindole-3-acetic acid (oxIAA) and salicylic acid (SA) were present in the biomass with significantly higher auxin content in the biomass generated using pig manure (> 350 pmol/g DW IAA and > 84 pmol/g DW oxIAA) compared to cultures enriched with Na-acetate and batch cultures (< 200 pmol/g DW IAA and < 27 pmol/g DW oxIAA). No abscisic acid and jasmonates were detected. All samples had plant biostimulating activity measured in the mungbean rooting bioassay with the Na-acetate supplemented biomass eliciting higher rooting activity (equivalent to 1–2 mg/l IBA) compared to the pig manure (equivalent to 0.5–1 mg/l IBA) and batch culture (equivalent to water control) generated biomass. Thus C. sorokiniana MACC-728 is a robust new strain for biotechnology, tolerating low light and temperature conditions. The strain can adapt to alternative nutrient (pig manure) and carbon (acetate) sources with the generated biomass having a high auxin concentration and plant biostimulating activity detected with the mungbean rooting bioassay.
Open Access: Yes
Salinity stress provokes diverse physiological responses of eukaryotic unicellular microalgae
Publication Name: Algal Research
Publication Date: 2023-06-01
Volume: 73
Issue: Unknown
Page Range: Unknown
Description:
Highly saline conditions represent a strong challenge for most microorganisms in freshwater ecosystems. Eukaryotic freshwater green algae from the Chlorophyta clade were investigated for their ability to survive in and adapt to increased salt concentration in the growth medium. Striking differences were detected between the responses of the various algae species to the elevated salt concentrations. The investigated Chlamydomonas reinhardtii cc124 and Coelastrella sp. MACC-549 algae showed a moderate resistance to increased salt concentration, while Chlorella sp. MACC-360 exhibited high salt tolerance, showed unaltered growth characteristics and photosynthetic efficiency compared to the saline-free control conditions even at 600 mM NaCl concentration. Diverse physiological responses to elevated salt concentrations were described for the tested algae including variations in their growth capacity, characteristic morphological changes, alterations in the structure and function of the photosynthetic machinery and differences in the production of reactive oxygen species. Special alterations were identified in the lipid and exopolysaccharide production patterns of the tested algal strains in response to high salinity. As a conclusion Chlorella sp. MACC-360 algae showed outstanding salt tolerance features. Together with the concomitant lipid-producing phenotype under highly saline conditions this unicellular green alga is a promising candidate for biotechnological applications.
Open Access: Yes
Evaluation of the biostimulant effects of two Chlorophyta microalgae on tomato (Solanum lycopersicum)
Publication Name: Journal of Cleaner Production
Publication Date: 2022-09-01
Volume: 364
Issue: Unknown
Page Range: Unknown
Description:
Eukaryotic microalgae from the Chlorophyta division are used in various bio-industries due to their ability to produce high value compounds. Some of these compounds show plant biostimulant properties when applied to plants, soil or growth medium in hydroponic chambers. The first objective of this study was to evaluate if Chlamydomonas reinhardtii cc 124 and Chlorella sp. MACC-360 had biostimulant effect on Solanum lycopersicum L. The second objective was to investigate the importance of the application mode and time. The third goal was to reveal strain-specific actions of the two algae strains. Tomato plants were grown in pots layered with clay at the bottom and filled with the mixture of soil and vermiculate. In two sets of experiments the soil and plant leaves were treated with living algae and algal extract, respectively. In the first set, the culture suspension (CS) was centrifuged, the algae pellet was re-suspended in water (CCS), and this was applied weekly to soil, while algae extract (cell disrupted algae suspension – CDS) was sprayed on leaves bi-weekly. The flowering process, plant morphology, fruit features and pigment contents were analyzed. In the second set of experiments, the culture suspension per se (CS) was applied to the soil weekly and CDS was sprayed on leaves bi-weekly. Flowering kinetics, reproductive capacity and photosynthetic parameters were examined. Both algae strains increased pigment content, fruit weight and fruit diameter of tomato. Plants that received initial algae treatment at an advanced age performed better than those initially treated at a young age. Chlorella induced early flowering and fruit development while Chlamydomonas significantly delayed these milestone functions. Chlorella promoted conversion of light energy to chemical energy, while Chlamydomonas enhanced protection of photosynthetic parameters. Both strains increased leaf temperature differential as well as leaf thickness. Overall, both algae strains stimulated important agronomic-valuable functions in tomato.
Open Access: Yes
Comparison of monocultures and a mixed culture of three Chlorellaceae strains to optimize biomass production and biochemical content in microalgae grown in a greenhouse
Publication Name: Journal of Applied Phycology
Publication Date: 2021-10-01
Volume: 33
Issue: 5
Page Range: 2755-2766
Description:
Light and temperature are important environmental conditions affecting microalgal growth in outdoor culture. It is essential to evaluate microalgae strains growing under outdoor conditions where they are subjected to variable environmental parameters. The present study investigated three Chlorellaceae strains (Micractinium sp. MACC-728, Chlorella sorokiniana MACC-438, and C. sorokiniana MACC-452) and a mixed culture combining these three strains. Cultures were grown in 2-L bioreactors in a greenhouse over 3 months to assess the effects of high temperature and light on their growth, macromolecule content, and antioxidant and plant-stimulating bioactivities. The most influential environmental parameters on growth were average air temperature and the sum of photosynthetically active radiation, followed by maximum air temperature. The most affected growth parameter was daily change in cell number. Chlorella sorokiniana MACC-438 produced the lowest biomass and was most affected by the high temperature and light conditions. Micractinium sp. produced the highest biomass and was least affected, suggesting it was the most suitable strain for outdoor cultivation. The mixed Chlorellaceae culture performed well in biomass production, exceeding C. sorokiniana monocultures but significantly underyielding in lipid content. Antioxidant activity and the root-stimulating activity varied with strain and culture age. Micractinium sp. had the highest but most variable antioxidant and plant-stimulating activity. Bioactivity in the mixed culture was more consistent, remaining high regardless of culture age and environmental conditions. Thus, mixed cultures of productive strains could be a useful strategy to ensure stable and high-quality biomass production in outdoor cultivation with fluctuating environmental conditions.
Open Access: Yes
Comparative and phylogenomic analysis of nuclear and organelle genes in cryptic Coelastrella vacuolata MACC-549 green algae
Publication Name: Algal Research
Publication Date: 2021-10-01
Volume: 58
Issue: Unknown
Page Range: Unknown
Description:
The nuclear, chloroplast and mitochondrial genomes of a unicellular green algal species of the Coelastrella genus was sequenced, assembled and annotated. The strain was previously classified as Chlamydomonas sp. MACC-549 based on morphology and partial 18S rDNA analysis. However, the proposed multi-loci phylogenomic approach described in this paper placed this strain within the Coelastrella genus, therefore it was re-named to Coelastrella vacuolata MACC-549. The strain was selected for de novo sequencing based on its potential value in biohydrogen production as revealed in earlier studies. This is the first thorough report and characterization for green algae from the Coelastrella genus. The whole genome annotation of Coelastrella vacuolata MACC-549 (including nuclear, chloroplast and mitochondrial genomes) shed light on interesting metabolic and sexual breeding features of this algae and served as a basis to taxonomically classify this strain.
Open Access: Yes
Strain-specific biostimulant effects of chlorella and chlamydomonas green microalgae on medicago truncatula
Publication Name: Plants
Publication Date: 2021-06-01
Volume: 10
Issue: 6
Page Range: Unknown
Description:
Microalgae have been identified to produce a plethora of bioactive compounds exerting growth stimulating effects on plants. The objective of this study was to investigate the plant-growth-promoting effects of three selected strains of eukaryotic green microalgae. The biostimulatory effects of two Chlorella species (MACC-360 and MACC-38) and a Chlamydomonas reinhardtii strain (cc124) were investigated in a Medicago truncatula model plant grown under controlled greenhouse conditions. The physiological responses of the M. truncatula A17 ecotype to algal biomass addition were characterized thoroughly. The plants were cultivated in pots containing a mixture of vermiculite and soil (1:3) layered with clay at the bottom. The application of live algae cells using the soil drench method significantly increased the plants’ shoot length, leaf size, fresh weight, number of flowers and pigment content. For most of the parameters analyzed, the effects of treatment proved to be specific for the applied algae strains. Overall, Chlorella application led to more robust plants with increased fresh biomass, bigger leaves and more flowers/pods compared to the control and Chlamydomonas-treated samples receiving identical total nutrients.
Open Access: Yes
Biomolecule composition and draft genome of a novel, high-lipid producing Scenedesmaceae microalga
Publication Name: Algal Research
Publication Date: 2021-04-01
Volume: 54
Issue: Unknown
Page Range: Unknown
Description:
Lipid biosynthesis in microalgae can be stimulated by cultivation in low nitrogen medium. MACC-401 was isolated from the soil surface in Tres Marias (MG-Brazil). The strain shows the morphological characteristics of the Scenedesmaceae green algae. The daily biomass and lipid production of MACC-401 is remarkable, 0.36 g L−1 and 110 mg L−1, respectively. Exploration of the genetic background of this promising strain not only allows the utilization of this species for industrial-scale lipid production, but also provides genetic targets to select lipid-producing strains from microalgae collections. We conducted physiological experiments by cultivating MACC-401 in complete and N-limited media and performed genome sequencing as well as transcriptome analysis. The estimated nuclear genome size of MACC-401 is 99.503 Mbp and the chloroplast genome is 0.15 Mbp. The phylogenetic analysis confirmed that the MACC-401 belongs to the Scenedesmaceae family, and represents a genetically distinct accession in this family. A basic comparative transcriptome analysis resulted in the identification of N-starvation responsive genes, which could serve as markers to monitor the onset of lipid accumulation in algal cultures.
Open Access: Yes
Phylogenetic re-evaluation of previously identified Chlamydomonas (Chlorophyta, Chlamydomonadaceae) strains from The Mosonmagyaróvár Algal Culture Collection, Hungary, using molecular data
Publication Name: South African Journal of Botany
Publication Date: 2019-09-01
Volume: 125
Issue: Unknown
Page Range: 16-23
Description:
Systematic studies on 70 MACC isolates previously identified as ‘Chlamydomonas’, a unicellular flagellate, were carried out based on partial 18S rRNA. The aim of this study was to determine the phylogenetic affiliations of Chlamydomonas strains in the MACC collection. The study found that most of the strains were not Chlamydomonas. Nine clusters of phylogenetically similar taxa were identified. The previous determinations were completed with their new phylogenetic affiliations (partly due to changes in green algae classification). Molecular data revealed that 3 of the 70 strains are from Arenicolinia, 14 are members of the phylogroup Stephanosphaerinia, 11 are Oogamochlamydinia, 1 is Chloromonadinia, 19 are Reinhardtinia, 2 are Polytominia, 9 are Scenedesmaceae, 5 are Moewusinia, and 6 are Chlorella. Clades were established by 18S rRNA similarity and p-distances. This study reveals the need to revise established culture collections whose isolates are solely identified with morphology.
Open Access: Yes
The reclassification of 37 strains from The Mosonmagyaróvár Algal Culture Collection, Hungary, which were previously identified as Anabaena (Cyanobacteria, Nostocaceae)
Publication Name: South African Journal of Botany
Publication Date: 2019-07-01
Volume: 123
Issue: Unknown
Page Range: 333-340
Description:
Study on 37 MACC isolates previously identified as “Anabaena,” a freshwater filamentous heterocytous taxon, were carried out using the 16S rRNA. The study found that most of the strains were misidentified at genus level. Three clusters of phylogenetically and morphologically similar taxa were identified. The previous determinations were amended with their new taxonomic classifications (partly due to changes in cyanobacterial classification). Some morphological structures could not be found in the cultures (e.g. akinetes). Molecular data revealed that 6 of the 37 strains are Desmonostoc, 8 are members of the genus Nostoc, 19 strains bear genetic resemblance to the genus Trichormus and 4 strains remain unresolved. Clades were established by 16S rRNA similarity and p-distances. The goal of this study was to amend the strain designations in this collection. This study reveals the necessity to revisit established culture collections that originally used only morphological classifications for species identification.
Open Access: Yes
Factors influencing algal photobiohydrogen production in algal-bacterial co-cultures
Publication Name: Algal Research
Publication Date: 2017-12-01
Volume: 28
Issue: Unknown
Page Range: 161-171
Description:
Algal-bacterial co-cultures represent an alternative way for algal biohydrogen generation. Efficient algal hydrogen production requires anaerobiosis and electrons accessible for the algal FeFe‑hydrogenases. A number of factors strongly influence the development of this optimal environment. Various algal strains were tested for hydrogen evolution with a selected bacterial partner, a fully hydrogenase deficient Escherichia coli. During the hunt for the most efficient algae strains, gas-to-liquid phase ratio, algal optical density and algal cell size were identified as crucial factors influencing algal hydrogen evolution rate, accumulated algal hydrogen yield, carbon dioxide and oxygen levels as well as acetic acid consumption in illuminated algal-bacterial cultures. The highest accumulated hydrogen yields were observed for the different algal partners under similar experimental setup. The combination of a gas-to-liquid phase ratio of 1/1 with an algae cell density of 3.96 ∗ 108 algae cell ml− 1 (OD750 : 1) resulted in the highest accumulated algal hydrogen yields under continuous illumination of ~ 50 μmol m− 2 s− 1 light at 25 °C irrespective of the applied algae strain. Accumulated hydrogen yield was also strongly influenced by the algal cell size, smaller cell size correlated with higher hydrogen evolution rate. The highest accumulated algal hydrogen yield (88.98 ± 2.19 ml H2 l− 1 d− 1) was obtained with Chlorella sp. MACC 360 -E. coli ΔhypF co-culture.
Open Access: Yes
