1,721,073 research outputs found
Microbial secreted exopolysaccharides of induced biological soil crusts in Inner Mongolian desert soils: chemical characteristics and role in affecting water-soil relations
No full textRole of polysaccharides produced by cyanobacteria in affecting the structure and the hydrological properties of the soi
Biological soil crusts: from ecology to biotechnology
No full textWhile the beneficial effects of algalization to improve agricultural fields are well known, a limited number of inoculation studies
have been so far carried out in prohibitive constrained ecosystems, where soil is unconsolidated, with very limited nutrient levels and high
abiotic stress levels. Recent results show that some cyanobacterial strains such as the non-heterocystous exopolysaccharide-producer
Microcoleus vaginatus, are able to grow in such conditions developing quickly into biological soil crusts, kicking off beneficial microbiological
processes potentially able to shift the state of the environment. This paper reviews the state of the art of this technology, pointing
out the existing gaps to fulfill in order to address different issues, including land rehabilitation and desertification counteractio
The induction of biological soil crusts: an environmental biotechnology based on the exploitation of phototrophic microorganisms
No full textThe lecture was focused on the recent results obtained by applying the biotechnology based on large scale cyanobacterial inoculation and BSC induction, and stresses how the potential of cyanobacterial inoculation can be translated in a flexible technology applicable in different contexts such as the stabilization and fertilization of aeolian sandy lands in arid and semiarid environment
Complex role of the exopolysaccharidic matrix in biological soil crusts
No full textIn arid and semiarid environments, soil carbon sequestration (CO2 fixation) by
cyanobacteria and by biological soil crusts (BSC) is considered an eco-friendly and natural
process to increase soil C content and a viable pathway to contrast desertification and to favor
soil rehabilitation. Within this context, inoculation-based techniques with exopolysaccharideproducing cyanobacteria have proved to be a viable and sustainable pathway to increase soil
biomass, soil stabilization, and to increase soil fertility. In this presentation, a particular focus
will be given on the role of the extracellular polysaccharidic matrix (EPM) synthesized by
cyanobacteria in giving the structure to natural or induced BSCs and to enhance their water
trapping and retaining capability. EPM was extracted with methods aimed at separately
removing the tightly bound exopolysaccharidic fraction (TB-EPS) and the loosely bound
exopolysaccharidic fraction (colloidal EPS; C-EPS) from BSCs having different ages. The
fractions were analyzed in terms of monosaccharidic composition, and molecular weight (MW)
distribution. We observed that the relative amounts of uronic acids increase in the EPM with the
age of the crusts, implying advantages for the community-water relations. In addition, we also
Abstracts – Third International Workshop on Biological Soil Crusts
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observed significant differences in MW distribution between the two EPS fractions, being TBEPS mostly composed by one molecular fraction having high MW, while C-EPS showed to be
also composed by low MW fractions. This difference suggests distinct roles of TB-EPS and CEPS fractions within the crust system. Indeed, TB-EPS most likely affects BSC structure and
water-retaining properties, while C-EPS most likely contributes to the intake of C in the soil,
thus favoring the growth of the chemoheterotrophic microbial community. The role of EPM in
water capture from non-rainfall sources, water maintenance at the topsoil, and in maintaining a
high water potential was also shown
Produzione di idrogeno con batteri fotosintetici da effluente di impianto di biometanazione di residui dell’agroindustria
No full textHydrogen is a clean fuel. Its combustion produces just water and energy. The opportunity of obtaining renewable energy from vegetable residues largely available makes
microbiological processes an interesting perspective. Aim of this research activity was to evaluate the possibility of inserting the photofermentative hydrogen producing process after or in between the acidogenic and/or methanogenic stages. The whole process was conducted starting from selected vegetable residues deriving from department stores. The study showed how the characteristics of the vegetable substrate chosen had an influence on the whole process; a high conversion yield of the substrate to energy was obtained when producing hydrogen by photofermentation using the effluent of the acidogenic stage as a substrate.
Furthermore, light intensity showed to be very important for obtaining better production rates. Indeed, the only possible applicative solutions for proposing photobiological hydronen production as an economically and energetically sustainable process are the use of both wastes as substrates and sunlight as the light source
Drought-tolerant cyanobacteria and mosses as biotechnological tools to attain land degradation neutrality
Get PDFThe induction of biocrusts through inoculation-based techniques has gained increasing scientific attention in the last 2 decades due to its potential to address issues related to soil degradation and desertification. The technology has shown the most rapid advances in the use of biocrust organisms, particularly cyanobacteria and mosses, as inoculants and biocrust initiators. Cyanobacteria and mosses are poikilohydric organisms - i.e., desiccation-tolerant organisms capable of reactivating their metabolism upon rehydration - that can settle on bare soils in abiotically stressing habitats, provided that selected species are used and an appropriate and customized protocol is applied. The success of inoculation of cyanobacteria and mosses depends on the inoculant's physiology, but also on the ability of the practitioner to identify and control, with appropriate technical approaches in each case study, those environmental factors that most influence the inoculant settlement and its ability to develop biocrusts.This review illustrates the current knowledge and results of biocrust induction biotechnologies that use cyanobacteria or mosses as inoculants. At the same time, this review's purpose is to highlight the current technological gaps that hinder an efficient application of the technology in the field
Polysaccharidic matrix formation in induced biocrusts is affected by soil type and inoculated cyanobacterial species
No full textThe induction of biocrusts by inoculating soils with cyanobacteria has been proposed as a sustainable technique for restorating degraded areas owing to the role that cyanobacteria and the exopolysaccharides (EPS) they secrete play in improving soil properties. Nonetheless, only few studies have analyzed the characteristics of the EPS matrix excreted by cyanobacteria in soil crusts, so far only focusing on sandy soil textures.
The objective of this study was to examine the characteristics of the EPS matrix induced under lab conditions by inoculating two cyanobacteria, Phormidium ambiguum (non N-fixing) and Scytonema javanicum (N-fixing), on four differently textured soils and to follow for 90 days the development of biocrusts, measuring their physical and ochemical features.
Cyanobacteria inoculation led to biocrust formation in all soil types, especially in those with .... texture. SEM images showed that the biocrusts induced by P. ambiguum were characterized by a dense, entangled network of thin filaments enveloping soil particles, while those induced by S. javanicum consisted of bunches of thicker filaments grouped in between soil particles.
S. javanicum promoted a higher release in the soil of the less condensed EPS fraction (LB-EPS), while P. ambiguum showed a higher release of the more condensed EPS fraction (TB-EPS). LB-EPSs were mainly composed of low MW molecules, while TB-EPSs were mainly composed of high MW molecules. The two EPS fractions showed a complex monosaccharidic composition (from 11 to 12 different types of monosaccharides), with glucose as the most abundant monosaccharide, in particular in the poorer soils poorer , characterized by lowerin organic C contents. Cyanobacteria inoculation also improved soil fertility, in particular in those soils that originally were less fertile.
Our results point out that both the development of induced biocrusts and the characteristics of the EPS matrix are significantly affected by the cyanobacterial species inoculated and by the texture of the soil treated
Biological soil crusts from High Arctic Environments: taxonomic composition of the prokaryotic community and characterization of exopolysaccharidic matrix
No full textSviluppo di croste biologiche in ambiente artic
Introducing capnophilic lactic fermentation in a combined dark-photo fermentation process: a route to unparalleled H2 yields
No full textTwo-stage process based on photofermentation of dark fermentation effluents is widely recognized as the most effective method for biological production of hydrogen from organic substrates. Recently, it was described an alternative mechanism, named capnophilic lactic fermentation, for sugar fermentation by the hyperthermophilic bacterium Thermotoga neapolitana in CO2-rich atmosphere. Here, we report the first application of this novel process to two-stage biological production of hydrogen. The microbial system based on T. neapolitana DSM 4359T and Rhodopseudomonas palustris 42OL gave 9.4 mol of hydrogen per mole of glucose consumed during the anaerobic process, which is the best production yield so far reported for conventional two-stage batch cultivations. The improvement of hydrogen yield correlates with the increase in lactic production during capnophilic lactic fermentation and takes also advantage of the introduction of original conditions for culturing both microorganisms in minimal media based on diluted sea water. The use of CO2 during the first step of the combined process establishes a novel strategy for biohydrogen technology. Moreover, this study opens the way to cost reduction and use of salt-rich waste as feedstock
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