-
Frontiers in Bioengineering and... 2023Pullulan has many potential applications in the food, pharmaceutical, cosmetic and environmental industries. However, the yield and molecular properties of pullulan...
Pullulan has many potential applications in the food, pharmaceutical, cosmetic and environmental industries. However, the yield and molecular properties of pullulan produced by various strains still need to be promoted to fit the application needs. A novel yeast-like strain BL06 producing high molecular weight (Mw) pullulan (3.3 × 10 Da) was isolated and identified in this study. The remarkable Mw of pullulan produced by BL06 was the highest level ever reported thus far. To further regulate the biosynthesis of pullulan in BL06, three gene knockout strains BL06 ΔPMAs, BL06 Δmel, and BL06 ΔPMAsΔmel, were constructed. The results showed that BL06 ΔPMAs could produce 140.2 g/L of moderate Mw (1.3 × 10 Da) pullulan after 120 h of fermentation. The highest yield level of pullulan to date could vastly reduce its production cost and expand its application scope and potential. The application experiments in food preservation showed that the moderate-Mw pullulan obtained in this work could reduce the weight loss of celery cabbages and mangos by 12.5% and 22%, respectively. Thus, the novel strains BL06 and BL06 ΔPMAs possessed unlimited development prospects in pullulan production at various Mw ranges and pullulan applications in multiple fields.
PubMed: 36777253
DOI: 10.3389/fbioe.2023.1131875 -
Foods (Basel, Switzerland) Feb 2023The ability of the fungus to regulate metabolism on various nitrogen sources makes it survive and metabolize in different environments. The biomass and the β-glucan...
The ability of the fungus to regulate metabolism on various nitrogen sources makes it survive and metabolize in different environments. The biomass and the β-glucan yield of are closely associated with the nitrogen source. This study found the only GATA nitrogen source activation regulating factor in HIT-LCY. In order to testify the function, we amplified its conserved domain to build a silencing vector and used the RNAi to obtain the silent strain, and then explored its effect on the phenotype of and the yield of β-glucan. We found that the biomass and β-glucan yield of the silent strain decreased significantly after culturing with different nitrogen sources, in particular when using sodium nitrate and glutamate as the source. However, the β-glucan yield increased significantly after overexpression of Area, reaching 5.2 g/L when glutamine was the nitrogen source. In addition, the strain morphology changed as well under different nitrogen sources. At last, we investigated the antioxidant activity in vitro of β-glucan and found that it has a significant clearance effect on OH·, DPPH·, and ABTS·, being best with ABTS. Therefore, this study believed that the Area gene has a certain regulation function on the synthesis of β-glucan with antioxidant activity.
PubMed: 36766189
DOI: 10.3390/foods12030660 -
Plants (Basel, Switzerland) Jan 2023is an important pathogenic fungus affecting many crops and is one of the main sources of their aflatoxin contamination. The primary method of limiting this pathogen is...
is an important pathogenic fungus affecting many crops and is one of the main sources of their aflatoxin contamination. The primary method of limiting this pathogen is using chemical fungicides, but researchers focus on searching for other effective agents for its control due to many disadvantages and limitations of these agrochemicals. The results obtained in the present study indicate the high potential of two yeast strains, PP4 and ZD1, in the biological control of Under in vitro conditions, mycelial growth was reduced by 53.61% and 63.05%, and spore germination was inhibited by 68.97% and 79.66% by ZD1 and PP4 strains, respectively. Both strains produced the lytic enzymes chitinase and β-1,3-glucanase after 5 days of cultivation with cell wall preparations (CWP) of in the medium as a carbon source. In addition, the tested yeasts showed the ability to grow over a wide range of temperatures (4-30 °C), pH (4-11), and salinity (0-12%) and showed tolerance to fungicides at concentrations corresponding to field conditions. Both isolates tested were highly tolerant to cupric oxychloride, showing biomass gains of 85.84% (ZD1) and 87.25% (PP4). Biomass growth in the presence of fungicides azoxystrobin was 78.71% (ZD1) and 82.65% (PP4), while in the presence of difenoconazole, it was 70.09% (ZD1) and 75.25% (PP4). The yeast strains were also tested for antagonistic effects against directly on tomato fruit. Both isolates acted effectively by reducing lesion diameter from 29.13 mm (control) to 8.04 mm (PP4) and 8.83 mm (ZD1).
PubMed: 36678949
DOI: 10.3390/plants12020236 -
Life (Basel, Switzerland) Jan 2023Unique natural objects, such as the caves of the Gobustan National Historical and Artistic Preserve, are also of great cultural and historical value due to rock art and...
Unique natural objects, such as the caves of the Gobustan National Historical and Artistic Preserve, are also of great cultural and historical value due to rock art and sites of ancient people. A favorable microclimate makes these habitats convenient for colonization by microbiota, including phototrophs. In arid regions with intense seasonal fluctuations of microclimatic parameters, the conditions for survival are the least favorable; therefore, it becomes especially important to determine the composition of communities that are the most adapted to specific conditions. This work aimed to identify the biodiversity of communities of caves and grottoes of the Gobustan Reserve. The studies were carried out in July 2019. Samples were analyzed for cyanobacteria and algae by microscopy and cultivation methods, microfungi were isolated by soil dilution, and the fouling glass method was also used. In total, 29 taxa of cyanobacteria and algae, 18 taxa of fungi, and 3 species of mosses were identified. The studied habitats were dominated by the algae Chlorella vulgaris, Aphanocapsa sp., and Stichococcus bacillaris; the subdominants were Jaaginema subtilissimum, Leptolyngbya tenuis, Chlorococcum minutum, and Humidophila contenta. Microfungi had the highest occurrence of Aspergillus niger, Aureobasidium pullulans, Alternaria alternata, and Talaromyces ruber. It was noted that cyanobacteria dominated in morphologically differentiated biofilms and green algae on the rocks. The greatest number of microfungi was found in the aphotic zone and bryophyte tufts. The dominance of green algae is atypical for most caves of other regions and may be associated with intense lighting of habitats. The absence of protonema is a consequence of the aridity and low moisture content of the substrates.
PubMed: 36676113
DOI: 10.3390/life13010164 -
World Journal of Microbiology &... Dec 2022Phosphorus (P) is one of the essential elements that are necessary for plant development and growth. However, the availability of soluble forms of P for plants in the...
Phosphorus (P) is one of the essential elements that are necessary for plant development and growth. However, the availability of soluble forms of P for plants in the soils is limited, because a large proportion of it is bound to soil constituents. Thus, the concentration of P available to plants at any time is very low and, moreover, its availability depends on the soil pH. As a solution, phosphate-solubilizing microorganisms (PSMs) are employed that render inorganic P available to plants in soluble form. Thus far, research into PSMs has been insufficient, and only few such organisms have been considered for exploitation as microbial fertilizer strains. The characteristics of plant growth promotion with the plant-PSMs coculture system remain to be elucidated. In the current study, we report on the isolate Rhodosporidium paludigenum JYC100 that exhibits good performance for solubilizing calcium phosphate. We found that it can be regulated by the amount of soluble phosphate. Furthermore, R. paludigenum JYC100 promotes plant growth under specific conditions (P deficiency, but with insoluble phosphate) in different media and soil pots. In contrast, the yeast Aureobasidium pullulans JYC104 exhibited weak phosphate-solubilizing capacities and no plant growth-promoting ability. Compared to control plants, the biomass, shoot height, and cellular inorganic P content of plants increased in plants cocultivated with R. paludigenum JYC100. In addition, histochemical GUS and qRT-PCR assays of phosphate starvation-induced (PSI) genes showed that the transcript levels of these PSI genes are decreased in the plants cocultured with R. paludigenum JYC100. These findings reflect the unique ability of R. paludigenum JYC100 to convert insoluble P compounds to plant-available P, thereby leading to growth promotion. Our study results highlight the use of yeasts as potential substitutes for inorganic phosphate fertilizers to meet the P demands of plants, which may eventually improve yields in sustainable agricultures.
Topics: Phosphates; Plant Development; Yeasts; Soil; Plants; Biological Products; Soil Microbiology
PubMed: 36565394
DOI: 10.1007/s11274-022-03498-9 -
Frontiers in Nutrition 2022Herein, we present a method for producing water-soluble polysaccharides (WSPs) by co-culture fermentation of straw and shrimp shells. The chitin-degrading strain was...
Herein, we present a method for producing water-soluble polysaccharides (WSPs) by co-culture fermentation of straw and shrimp shells. The chitin-degrading strain was isolated and genotypically identified as the non-pathogen sp. LYM-1 in this study. sp. LYM-1 and 2012 could coexist without antagonism. WSPs concentrations were higher in co-culture fermentations of sp. LYM-1 and 2012 (PsL/AP-WSPs) compared to monocultures (PsL-WSPs and AP-WSPs). FTIR was used to examine the polysaccharide properties of three WSP fractions. The monosaccharide compositions of three WSPs fractions were primarily composed of mannose, ribose, glucosamine, glucose, galactose, and arabinose with varying molecular weights and molar ratios according to HPLC analysis. PsL/AP-WSPs showed better scavenging effects on DPPH, ABTS, and OH free radicals, demonstrating the application potential of PsL/AP-WSPs from straw and shrimp shells. The maximum yield obtained under optimum conditions (fermentation time of 6 days, temperature of 31°C, inoculum concentration of 10% (w/v), and inoculum composition of 2:1) was 5.88 ± 0.40 mg/mL, based on the PsL/AP-WSPs production optimization by orthogonal design. The results suggest that an environmentally friendly approach for WSPs production from agro-food wastes straw and shrimp shells was developed.
PubMed: 36479299
DOI: 10.3389/fnut.2022.1047932 -
Synthetic and Systems Biotechnology Mar 2023The current petroleum chemical methods for fumaric acid production can cause heavy pollution and global warming. In this study, the engineered strains of var. were...
The current petroleum chemical methods for fumaric acid production can cause heavy pollution and global warming. In this study, the engineered strains of var. were found to be suitable for green fumaric acid producer. Removal and complementation of the relevant genes showed only the ornithine-urea cycle (OUC) was involved in high level fumarate biosynthesis which was controlled by the Ca signaling pathway. Removal of both the gene encoding glucose oxidase and the gene encoding the polyketide synthase for 3,5-dihydroxydecanoic acid biosynthesis and overexpression of the gene encoding pyruvate carboxylase made the strain e-PYC produce 88.1 ± 4.3 g/L of fumarate at flask level and 93.9 ± 0.8 g/L of fumarate during the fed-batch fermentation. As a yeast-like fungal strain, it was very easy to cultivate var. DH177 and their mutants in the bioreactor and to edit its genomic DNAs to enhance fumarate production. It was found that 2 mol of CO could be fixed during a maximal theoretical yield of 2 mol of fumarate per mole of glucose consumed in the OUC. Therefore, the OUC-mediated fumarate biosynthesis pathway in var. was a green and eco-friendly process for the global sustainable development and carbon neutrality.
PubMed: 36381963
DOI: 10.1016/j.synbio.2022.10.004 -
Microorganisms Nov 2022The aim of this study was to investigate fungal communities associated with leaves and roots of healthy-looking and declining U. glabra trees. The study was expected to...
The aim of this study was to investigate fungal communities associated with leaves and roots of healthy-looking and declining U. glabra trees. The study was expected to demonstrate whether and how the diversity and composition of fungal communities change in these functional tissues following the infection by Dutch elm disease-causing fungi. The study sites included six U. glabra sites in Lithuania, where leaves and roots were sampled. DNA was isolated from individual samples, amplified using ITS2 rRNA as a marker, and subjected to high-throughput sequencing. The sequence analysis showed the presence of 32,699 high-quality reads, which following clustering, were found to represent 520 non-singleton fungal taxa. In leaves, the fungal species richness was significantly higher in healthy-looking trees than in diseased ones (p < 0.05). In roots, a similar comparison showed that the difference was insignificant (p > 0.05). The most common fungi in all samples of roots were Trichocladium griseum (32.9%), Penicillium restrictum (21.2%), and Unidentified sp. 5238_7 (12.6%). The most common fungi in all samples of leaves were Trichomerium sp. 5238_8 (12.30%), Aureobasidium pullulans (12.03%), Cladosporium sp. 5238_5 (11.73%), and Vishniacozyma carnescens (9.86%). The results showed that the detected richness of fungal taxa was higher in samples collected from healthy-looking trees than from diseased ones, thereby highlighting the negative impact of the Dutch elm disease on the overall fungal diversity.
PubMed: 36363820
DOI: 10.3390/microorganisms10112228 -
BMC Genomic Data Nov 2022Zalaria sp. Him3 was reported as a novel fructooligosaccharides (FOS) producing yeast. However, Zalaria spp. have not been widely known and have been erroneously...
BACKGROUND
Zalaria sp. Him3 was reported as a novel fructooligosaccharides (FOS) producing yeast. However, Zalaria spp. have not been widely known and have been erroneously classified as a different black yeast, Aureobasidium pullulans. In this study, de novo genome assembly and analysis of Zalaria sp. Him3 was demonstrated to confirm the existence of a potential enzyme that facilitates FOS production and to compare with the genome of A. pullulans.
RESULTS
The genome of Zalaria sp. Him3 was analyzed; the total read bases and total number of reads were 6.38 Gbp and 42,452,134 reads, respectively. The assembled genome sequence was calculated to be 22.38 Mbp, with 207 contigs, N50 of 885,387, L50 of 10, GC content of 53.8%, and 7,496 genes. g2419, g3120, and g3700 among the predicted genes were annotated as cellulase, xylanase, and β-fructofuranosidase (FFase), respectively. When the read sequences were mapped to A. pullulans EXF-150 genome as a reference, a small amount of reads (3.89%) corresponded to the reference genome. Phylogenetic tree analysis, which was based on the conserved sequence set consisting of 2,362 orthologs in the genome, indicated genetic differences between Zalaria sp. Him3 and Aureobasidium spp.
CONCLUSION
The differences between Zalaria and Aureobasidium spp. were evident at the genome level. g3700 identified in the Zalaria sp. Him3 likely does not encode a highly transfructosyl FFase because the motif sequences were unlike those in other FFases involved in FOS production. Therefore, strain Him3 may produce another FFase. Furthermore, several genes with promising functions were identified and might elicit further interest in Zalaria yeast.
Topics: Saccharomyces cerevisiae; Phylogeny; Ascomycota; beta-Fructofuranosidase
PubMed: 36357835
DOI: 10.1186/s12863-022-01094-2 -
Journal of Clinical and Experimental... 2022Non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH) are highly prevalent conditions characterized by inflammation and fibrosis of the...
BACKGROUND
Non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH) are highly prevalent conditions characterized by inflammation and fibrosis of the liver, which can progress to cirrhosis and hepatocellular carcinoma if left untreated. Conventional modalities are mainly symptomatic, with no definite solution. Beta-glucan-based biological response modifiers are a potential strategy in lieu of their beneficial metabolic effects. strains AFO-202 and N-163 beta-glucans were evaluated for anti-fibrotic and anti-inflammatory hepatoprotective potentials in a NASH animal model in this study.
METHODS
In the STAM™ murine model of NASH, five groups were studied for 8 weeks: (1) vehicle (RO water), (2) AFO-202 beta-glucan; (3) N-163 beta-glucan, (4) AFO-202+N-163 beta-glucan, and (5) telmisartan (standard pharmacological intervention). Evaluation of biochemical parameters in plasma and hepatic histology including Sirius red staining and F4/80 immunostaining were performed.
RESULTS
AFO-202 beta-glucan significantly decreased inflammation-associated hepatic cell ballooning and steatosis. N-163 beta-glucan decreased fibrosis and inflammation significantly ( value < 0.05). The combination of AFO-202 with N-163 significantly decreased the NAFLD Activity Score (NAS) compared with other groups.
CONCLUSION
This preclinical study supports the potential of N-163 and AFO-202 beta-glucans alone or in combination as potential preventive and therapeutic agent(s), for NASH.
PubMed: 36340302
DOI: 10.1016/j.jceh.2022.06.008