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Microbial Biotechnology May 2021Microbially induced calcite precipitation (MICP), secreted through biological metabolic activity, secured an imperative position in remedial measures within the...
Microbially induced calcite precipitation (MICP), secreted through biological metabolic activity, secured an imperative position in remedial measures within the construction industry subsequent to ecological, environmental and economical returns. However, this contemporary recurrent healing system is susceptible to microbial depletion in the highly alkaline cementitious environment. Therefore, researchers are probing for alkali resistant calcifying microbes. In the present study, alkaliphilic microbes were isolated from different soil sources and screened for probable CaCO precipitation. Non-ureolytic pathway (oxidation of organic carbon) was adopted for calcite precipitation to eliminate the production of toxic ammonia. For this purpose, calcium lactate Ca(C H O ) and calcium acetate Ca(CH COO) were used as CaCO precipitation precursors. The quantification protocol for precipitated CaCO was established to select potent microbial species for implementation in the alkaline cementitious systems as more than 50% of isolates were able to precipitate CaCO . Results suggested 80% of potent calcifying strains isolated in this study, portrayed higher calcite precipitation at pH 10 when compared to pH 7. Ten superlative morphologically distinct isolates capable of CaCO production were identified by 16SrRNA sequencing. Sequenced microbes were identified as species of Bacillus, Arthrobacter, Planococcus, Chryseomicrobium and Corynebacterium. Further, microstructure of precipitated CaCO was inspected through scanning electron microscopy (SEM), X-ray diffraction (XRD) and thermal gravimetric (TG) analysis. Then, the selected microbes were investigated in the cementitious mortar to rule out any detrimental effects on mechanical properties. These strains showed maximum of 36% increase in compressive strength and 96% increase in flexural strength. Bacillus, Arthrobacter, Corynebacterium and Planococcus genera have been reported as CaCO producers but isolated strains have not yet been investigated in conjunction with cementitious mortar. Moreover, species of Chryseomicrobium and Glutamicibacter were reported first time as calcifying strains.
Topics: Bacillus; Bacteria; Calcium Carbonate; Chemical Precipitation; Feasibility Studies
PubMed: 33629805
DOI: 10.1111/1751-7915.13752 -
Frontiers in Microbiology 2021Protease-producing bacteria play vital roles in degrading organic matter of aquaculture system, while the knowledge of diversity and bacterial community structure of...
Protease-producing bacteria play vital roles in degrading organic matter of aquaculture system, while the knowledge of diversity and bacterial community structure of protease-producing bacteria is limited in this system, especially in the tropical region. Herein, 1,179 cultivable protease-producing bacterial strains that belonged to Actinobacteria, Firmicutes, and Proteobacteria were isolated from tropical aquaculture systems, of which the most abundant genus was , followed by . The diversity and relative abundance of protease-producing bacteria in sediment were generally higher than those in water. Twenty-one genera from sediment and 16 genera from water were identified, of which dominated by in both and dominated by in water were the dominant genera. The unique genera in sediment or water accounted for tiny percentage may play important roles in the stability of community structure. Eighty isolates were clustered into four clusters (ET-1-ET-4) at 58% of similarity by ERIC-PCR (enterobacterial repetitive intergenic consensus-polymerase chain reaction), which was identified as a novel branch of . Additionally, strains belonged to ET-3 and ET-4 were detected in most aquaculture ponds without outbreak of epidemics, indicating that these protease-producing bacteria may be used as potential beneficial bacteria for wastewater purification. Environmental variables played important roles in shaping protease-producing bacterial diversity and community structure in aquaculture systems. In sediment, dissolved oxygen (DO), chemical oxygen demand (COD), and salinity as the main factors positively affected the distributions of dominant genus () and unique genera ( and ), whereas temperature negatively affected that of (except ). In water, as unique genus and were negatively affected by NO -N and NO -N, respectively, whereas pH as the main factor positively affected the distribution of . These findings will lay a foundation for the development of protease-producing bacterial agents for wastewater purification and the construction of an environment-friendly tropical aquaculture model.
PubMed: 33613508
DOI: 10.3389/fmicb.2021.638129 -
Life (Basel, Switzerland) Jan 2021(1) Background: Future missions to potentially habitable places in the Solar System require biochemistry-independent methods for detecting potential alien life forms....
(1) Background: Future missions to potentially habitable places in the Solar System require biochemistry-independent methods for detecting potential alien life forms. The technology was not advanced enough for onboard machine analysis of microscopic observations to be performed in past missions, but recent increases in computational power make the use of automated in-situ analyses feasible. (2) Methods: Here, we present a semi-automated experimental setup, capable of distinguishing the movement of abiotic particles due to Brownian motion from the motility behavior of the bacteria . Supervised machine learning algorithms were also used to specifically identify these species based on their characteristic motility behavior. (3) Results: While we were able to distinguish microbial motility from the abiotic movements due to Brownian motion with an accuracy exceeding 99%, the accuracy of the automated identification rates for the selected species does not exceed 82%. (4) Conclusions: Motility is an excellent biosignature, which can be used as a tool for upcoming life-detection missions. This study serves as the basis for the further development of a microscopic life recognition system for upcoming missions to Mars or the ocean worlds of the outer Solar System.
PubMed: 33445805
DOI: 10.3390/life11010044 -
PeerJ 2020Numerous bacteria entered the viable but non-culturable state due to the stresses of dry and salt in soils. YeaZ of Gram-negative bacteria is a resuscitation promoting...
Numerous bacteria entered the viable but non-culturable state due to the stresses of dry and salt in soils. YeaZ of Gram-negative bacteria is a resuscitation promoting factor (Rpf) homologous protein could resuscitate bacteria of natural environment in VBNC state. To investigate the promoting effect of YeaZ on the isolation of viable but non-culturable (VBNC) bacteria from soil samples in extreme environments, the recombinant YeaZ of was prepared and added to the soil samples from volcanic soil and saline soil in Northwest China. The study has shown that YeaZ can promote the recovery and growth of soil microorganisms, and the number of cultivable bacteria in volcanic and saline soil has increased from 0.17 × 10 and 2.03 × 10 cfu⋅ml to 1.00 × 10 and 5.55 × 10 cfu⋅ml, respectively. The 16S rDNA gene sequencing and phylogenetic analysis showed that YeaZ played an essential role in the increase of composition and diversity of bacteria. A total of 13 bacterial strains were isolated from the volcanic soil samples, which belong to phyla Actinobacteria, Firmicutes and Gamma-proteobacteria. Four species, including , , and were found in the control group, while , , , , and were isolated from the treatment groups (addition of YeaZ). Twenty-one strains were isolated from the saline soil samples, including eight species from the control group and thirteen species from the treatment groups, among which nine species were only found, including , , , , , , , and . The results suggest that addition of YeaZ to soil samples can promote the recovery of VBNC. This method has the implications for the discovery of VBNC bacteria that have potential environmental functions.
PubMed: 33391864
DOI: 10.7717/peerj.10342 -
Journal of Environmental Health Science... Dec 2020The aim of the present work was to assess the electrogenic activity of bacteria from hydrothermal vent sediments achieved under sulfate reducing (SR) conditions in a...
PURPOSE
The aim of the present work was to assess the electrogenic activity of bacteria from hydrothermal vent sediments achieved under sulfate reducing (SR) conditions in a microbial fuel cell design with acetate, propionate and butyrate as electron donors.
METHODS
Two different mixtures of volatile fatty acids (VFA) were evaluated as the carbon source at two chemical oxygen demand (COD) proportions. The mixtures of VFA used were: acetate, propionate and butyrate COD: 3:0.5:0.5 (stage 1) and acetate - butyrate COD: 3.5:0.5 (stage 2). Periodical analysis of sulfate (SO ), sulfide (HS) and COD were conducted to assess sulfate reduction (SR) and COD removal along with measurements of voltage and current to assess the global performance of the consortium in the system.
RESULTS
Percentage of SR was of 97.5 ± 0.7 and 74.3 ± 1.5% for stage 1 and 2, respectively. The % COD removal was of 91 ± 2.1 and 75.3 ± 9.6 for stage 1 and 2, respectively. Although SR and COD removal were higher at stage 1, in regards of energy, stage 2 presented higher current and power densities and Coulombic efficiency as follows: 741.7 ± 30.5 μA/m, 376 ± 34.4 μW/m and 5 ± 2.7%, whereas for stage 1 these values were: 419 ± 71 μA/m, 52.7 ± 18 μW/m and 0.02%, respectively. A metagenomic analysis - stage 2 - in the anodic chamber, demonstrated that SR was due to (), and and the electrogenic microorganisms were , , , , and families and .
CONCLUSIONS
It was demonstrated that microorganisms prevenient from hydrothermal vent sediments adapted to a microbial fuel cell system are able to generate electricity coupled to 74.3 ± 1.5 and 75.3 ± 9.6% of SR and COD removal respectively, with a mixture of acetate - butyrate.
PubMed: 33312634
DOI: 10.1007/s40201-020-00537-1 -
Frontiers in Microbiology 2020This study aims at exploiting salinity stress as an innovative, simple, and cheap method to enhance the production of antioxidant metabolites and enzymes from bacteria...
This study aims at exploiting salinity stress as an innovative, simple, and cheap method to enhance the production of antioxidant metabolites and enzymes from bacteria for potential application as functional additives to foods and pharmaceuticals. We investigated the physiological and biochemical responses of four bacterial isolates, which exhibited high tolerance to 20% NaCl (wt/vol), out of 27 bacterial strains isolated from Aushazia Lake, Qassim region, Saudi Arabia. The phylogenetic analysis of the 16S rRNA genes of these four isolates indicated that strains ST1 and ST2 belong to genus , whereas strains ST3 and ST4 belong to genus . Salinity stress differentially induced oxidative damage, where strains ST3 and ST4 showed increased lipid peroxidation, lipoxygenase, and xanthine oxidase levels. Consequently, high antioxidant contents were produced to control oxidative stress, particularly in ST3 and ST4. These two strains showed increased glutathione cycle, phenols, flavonoids, antioxidant capacity, catalase, and/or superoxide dismutase (SOD). Interestingly, the production of glutathione by strains was some thousand folds greater than by higher plants. On the other hand, the induction of antioxidants in ST1 and ST2 was restricted to phenols, flavonoids, peroxidase, glutaredoxin, and/or SOD. The hierarchical analysis also supported strain-specific responses. This is the first report that exploited salinity stress for promoting the production of antioxidants from bacterial isolates, which can be utilized as postbiotics for promising applications in foods and pharmaceuticals.
PubMed: 33042068
DOI: 10.3389/fmicb.2020.561816 -
Molecules (Basel, Switzerland) Sep 2020Antarctic regions are characterized by low temperatures and strong UV radiation. This harsh environment is inhabited by psychrophilic and psychrotolerant organisms,...
Antarctic regions are characterized by low temperatures and strong UV radiation. This harsh environment is inhabited by psychrophilic and psychrotolerant organisms, which have developed several adaptive features. In this study, we analyzed two Antarctic bacterial strains, sp. ANT_H30 and sp. ANT_H53B. The physiological analysis of these strains revealed their potential to produce various biotechnologically valuable secondary metabolites, including surfactants, siderophores, and orange pigments. The genomic characterization of ANT_H30 and ANT_H53B allowed the identification of genes responsible for the production of carotenoids and the in silico reconstruction of the pigment biosynthesis pathways. The complex manual annotation of the bacterial genomes revealed the metabolic potential to degrade a wide variety of compounds, including xenobiotics and waste materials. Carotenoids produced by these bacteria were analyzed chromatographically, and we proved their activity as scavengers of free radicals. The quantity of crude carotenoid extracts produced at two temperatures using various media was also determined. This was a step toward the optimization of carotenoid production by Antarctic bacteria on a larger scale.
Topics: Carotenoids; Genome, Bacterial; Genomics; Multigene Family; Phylogeny; Planococcus Bacteria; Rhodococcus
PubMed: 32977394
DOI: 10.3390/molecules25194357 -
Frontiers in Bioengineering and... 2020The marine environment represents a well-off and diverse group of microbes, which offers an enormous natural bioactive compounds of commercial importance. These natural... (Review)
Review
The marine environment represents a well-off and diverse group of microbes, which offers an enormous natural bioactive compounds of commercial importance. These natural products have expanded rigorous awareness due to their widespread stability and functionality under harsh environmental conditions. The genus is a halophilic bacterium known for the production of diverse secondary metabolites such as 2-acetamido-2-deoxy-α-d-glucopyranosyl-(1, 2)-β-d-fructofuranose exhibiting stabilizing effect and methyl glucosyl-3,4-dehydro-apo-8-lycopenoate displaying antioxidant activity. The genus is reported generally for hydrocarbon degradation in comparison with biosurfactant/bioemulsifier secretion. Although was proposed in 1894, it seized long stretch (till 1970) to get accommodated under the genus authentically. Large-scale biosurfactant production from was reported in 2014 with partial characterization. For the first time in 2019, we documented genomic and functional analysis of sp. along with the physico-chemical properties of its biosurfactant. In 2020, again we screened biosurfactant for pharmacological applications. The present review discusses the comprehensive genomic insights and physical properties of -derived biosurfactant. Moreover, we also highlight the prospects and challenges in biosurfactant production from sp. Among ∼102 reports on biosurfactant produced by marine bacteria, 43 were of glycolipid and 59 were non-glycolipid type. Under other biosurfactant type, they were identified as lipopeptide (20) like surfactin (5), glycolipoprotein/lipoprotein (12), and other non-glycolipid (22). sp. generally produces glycolipid-type biosurfactant (4) and exopolysaccharides (2). The single report documented in the literature is on biosurfactant production (glycolipid +non glycolipid) by diverse marine microbes (39) suggesting their novelty and diversity for biosurfactant secretion.
PubMed: 32974318
DOI: 10.3389/fbioe.2020.00996 -
MicrobiologyOpen Jun 2020Strain Y74 was an isolate from the sandy soil in the town of Huatugou, Qinghai-Tibet Plateau, China. An analysis of this strain's phenotypic, chemotaxonomic, and genomic...
Strain Y74 was an isolate from the sandy soil in the town of Huatugou, Qinghai-Tibet Plateau, China. An analysis of this strain's phenotypic, chemotaxonomic, and genomic characteristics established the relationship of the isolate with the genus Planococcus. Strain Y74 was able to grow between 4 and 42°C (with an optimum temperature of 28°C) at pH values of 6-8.5 and in 0%-7% (w/v) NaCl. The dominant quinones were MK-8 and MK-7. The polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, and an unknown phospholipid. The majority of the fatty acid content was anteiso-C (28.8%) followed by C ω7c alcohol (20.9%) and iso-C (13.4%). The 16S rRNA gene sequence similarity analysis demonstrated a stable branch formed by strain Y74 and Planococcus halotolerans SCU63 (99.66%). The digital DNA-DNA hybridization between these two strains was 57.2%. The G + C content in the DNA of Y74 was 44.5 mol%. In addition, the morphological, physiological, and chemotaxonomic pattern clearly differentiated the isolates from their known relatives. In conclusion, the strain Y74 (=JCM 32826 = CICC24461 ) represents a novel member of the genus Planococcus, for which the name Planococcus antioxidans sp. nov. is proposed. Strain Y74 was found to have potent antioxidant activity via its hydrogen peroxide tolerance and its 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity. The DPPH radical-scavenging activity was determined to be 40.2 ± 0.7%. The genomic analysis indicated that six peroxidases genes, one superoxide dismutase gene, and one dprA (DNA-protecting protein) are present in the genome of Y74 .
Topics: Antioxidants; Bacterial Typing Techniques; Base Composition; DNA, Bacterial; Fatty Acids; Genome, Bacterial; Planococcus Bacteria; Sequence Analysis, DNA; Soil Microbiology; Tibet; Whole Genome Sequencing
PubMed: 32162498
DOI: 10.1002/mbo3.1028 -
The Onderstepoort Journal of Veterinary... Jul 2019Several types of odours are involved in the location of host animals by tsetse (Diptera: Glossinidae), a vector of animal African trypanosomiasis. Host animals' ageing...
Several types of odours are involved in the location of host animals by tsetse (Diptera: Glossinidae), a vector of animal African trypanosomiasis. Host animals' ageing urine has been shown to be the source of a phenolic blend attractive to the tsetse. Nevertheless, limited research has been performed on the microbial communities' role in the production of phenols. This study aimed at profiling bacterial communities mediating the production of tsetse attractive phenols in mammalian urine. Urine samples were collected from African buffalo (Syncerus caffer), cattle (Bos taurus) and eland (Taurotragus oryx) at Kongoni Game Valley Ranch and Kenyatta University in Kenya. Urine samples, of each animal species, were pooled and left open to age in ambient conditions. Bacteriological and phenols analyses were then carried out, at 4 days ageing intervals, for 24 days. Phenols analysis revealed nine volatile phenols: 4-cresol, ortho-cresol, 3-cresol, phenol, 3-ethylphenol, 3-propylphenol, 2-methyloxyphenol, 4-ethylphenol and 4-propylphenol. Eight out of 19 bacterial isolates from the ageing urine revealed the potential to mediate production of phenols. 16S rRNA gene characterisation of the isolates closely resembled Enterococcus faecalis KUB3006, Psychrobacter alimentarius PAMC 27887, Streptococcus agalactiae 2603V, Morganella morganii sub.sp. morganii KT, Micrococcus luteus NCTC2665, Planococcus massiliensis strain ES2, Ochrobactrum pituitosum AA2 and Enterococcus faecalis OGIRF. This study established that some of the phenols emitted from mammalian urine, which influence the tsetse's host-seeking behaviour, are well characterised by certain bacteria. These results may allow the development of biotechnological models in vector control that combines the use of these bacteria in the controlled release of semiochemicals.
Topics: Animals; Antelopes; Bacteria; Buffaloes; Cattle; Chemotaxis; Kenya; Microbiota; Odorants; Phenols; RNA, Bacterial; RNA, Ribosomal, 16S; Tsetse Flies
PubMed: 31368325
DOI: 10.4102/ojvr.v86i1.1724