The huge amounts of keratin-rich waste generated daily by various industries, slaughterhouses, and processing plants need to be properly managed. Most keratin degradation-related research focuses on ...keratin from bird feathers, but a vast minority focuses on keratin from sheep wool, which also presents a serious environmental problem. In this article, we describe the isolation, identification, and characterization of new keratinolytic microorganisms capable of sheep wool degradation from sheep wool and soil enriched with wool keratin. We isolated four bacterial species from the genus
Bacillus
(
B. subtilis, B. altitudinis, B. mycoides
, and
B. wiedmannii
), one streptomycete species
Streptomyces coelicoflavus
identified by whole genome sequencing, and a fungal species
Aphanoascus reticulisporus
. In some of the isolated microorganisms, we detected keratinolytic activity for the first time, and for most of them, the ability to degrade sheep wool has not been previously demonstrated. The keratinases of the new isolates are active in a wide range of temperatures (25–85 °C) and pH (6.0–10.0), so all isolates show great potential for further biotechnological use in industry and in various environmental and agricultural applications to reduce and recycle keratin-rich wastes such as sheep wool and waste woollen textiles.
Every day many people suffer from intestinal diseases. These disorders can result from pathogens like bacteria, fungi, parasites and viruses, but the causes of non-infectious intestinal disorders and ...colorectal cancers remain to be elucidated. Disturbances to the normal gut flora (the microbiota) are central to the development of many, if not all, of these disorders. Disturbed gut microbiota is a prelude to public health issues like traveller's-, antibiotic- and Clostridium difficile-associated diarrhoea, irritable bowel syndrome, inflammatory bowel disease, and colorectal cancers. This book discusses the way intestinal disorders affect the microbiota, how the disturbed microbiotal balance leads to enteric disorders and the ways to prevent these disorders. Further his book explores the potential of probiotics (live microorganisms that when ingested bring a health benefit) in treating enteric disorders by analysing the probiotic genome through proteomics, metabolomics and functional assays. Discussed is how the ingestion of specific microorganisms repairs the disturbed microbiota and subsequently ameliorates enteric disorders. Finally this book addresses how genetic engineering and biotechnology will contribute to the development of effective and safe designer probiotics.
Liquid fraction produced in anaerobic digestion (AD) of biodegradable waste can be treated on-site with microalgae, which can be recycled back as substrate to the biogas plant. For this research, a ...pilot high rate algal pond (HRAP) was set with connections to a full scale biogas plant that enabled the use of waste heat and CO2 from a combined heat and power gen-set (CHP). The microalgal mix produced in the thermophilic anaerobic digestate supernatant was tested as a substrate for biogas production in the thermophilic AD (i.e. untreated, bioaugmented with anaerobic bacteria Clostridium thermocellum, and thermally pretreated, respectively). The methane potential of the untreated microalgal mix was low (157.5 ± 18.7 mL CH4/g VS). However, after the thermal pretreatment of the microalgae, methane production increased by 62%, while in the bioaugmentation with C. thermocellum under thermophilic conditions (T = 55 °C) it was elevated by 12%. The outcome of our pilot trial suggests that microalgae produced in the thermophilic biogas digestate represent a prospective alternative AD feedstock. At the same time, microalgae reduce the digestate nitrogen and COD to the level sufficient for the outflow to meet the quality required by the sewage system (ammonia-nitrogen max 200 mg/L, nitrite max 10 mg/L).
•A pilot plant for treating thermophilic anaerobic digestate supernatant with microalgae was constructed outdoor (89 m2).•The removal efficiency by algal treatment of digestate was 83–97% for NH4-N, and 81–95% for COD.•By a continuous 63-day treatment under favorable weather conditions 22.5 g of TS/day/m2 of a microalgal mix was produced.•Biomethane potential of thermally pretreated microalgal mix showed significantly elevated methane production (+62%).•Bioaugmentation with Clostridium thermocellum increased methane production from microalgal mix by 12%.
Herbivorous animals harbour potent cellulolytic and hemicellulolytic microorganisms that supply the host with nutrients acquired from degradation of ingested plant material. In addition to protozoa ...and fungi, rumen bacteria contribute a considerable part in the breakdown of recalcitrant (hemi)cellulosic biomass. The present review is focused on the enzymatic systems of three representative fibrolytic rumen bacteria, namely Ruminococcus flavefaciens, Prevotella bryantii and Pseudobutyrivibrio xylanivorans. R. flavefaciens is known for one of the most elaborated cellulosome architectures and might represent a promising candidate for the construction of designer cellulosomes. On the other hand, Prevotella bryantii and Pseudobutyrivibrio xylanivorans produce multiple free, but highly efficient xylanases. In addition, P. xylanivorans was also shown to have some probiotic traits, which makes it a promising candidate not only for biogas production, but also as an animal feed supplement. Genomic and proteomic analyses of cellulolytic and hemicellulolytic bacterial species aim to identify novel enzymes, which can then be cloned and expressed in adequate hosts to construct highly active recombinant hydrolytic microorganisms applicable for different biotechnological tasks.
The presence of endocrine-disrupting compounds in wastewater, surface water, groundwater and even drinking water has become a major concern worldwide, since they negatively affect wildlife and ...humans. Therefore, these substances should be effectively removed from effluents before they are discharged into surface water to prevent pollution of groundwater, which can be a source of drinking water. Furthermore, an efficient control of endocrine-disrupting compounds in wastewater based on biological and analytical techniques is required. In this study, a yeast estrogen screen (YES) bioassay has been introduced and optimized with the aim to assess potential estrogenic activity of waters. First, assay duration, concentration of added substrate to the assay medium and wavelength used to measure the absorbance of the substrate were estimated. Several compounds, such as 17-β-estradiol, 17-α-ethinylestradiol, bisphenol A, nonylphenol, genisteine, hydrocortisone, dieldrin, atrazine, methoxychlor, testosterone and progesterone were used to verify its specificity and sensitivity. The optimized YES assay was sensitive and responded specifically to the selected estrogenic and nonestrogenic compounds in aqueous samples. Potential estrogenicity of influent and effluent samples of two wastewater treatment plants was assessed after the samples had been concentrated by solid-phase extraction (SPE) procedure using Oasis® HLB cartridges and methanol as eluting solvent. Up to 90 % of relative estrogenic activity was detected in concentrated samples of influents to wastewater treatment plants and estrogenic activity was still present in the concentrated effluent samples. We found that the introduced YES assay is a suitable screening tool for monitoring the potential estrogenicity of effluents that are discharged into surface water. Key words: endocrine-disrupting compounds, estrogenic activity, monitoring, solid-phase extraction, yeast estrogen screen assay, water
Ruminococcus flavefaciens is an important fibre-degrading bacterium found in the mammalian gut. Cellulolytic strains from the bovine rumen have been shown to produce complex cellulosome structures ...that are associated with the cell surface. R. flavefaciens 007 is a highly cellulolytic strain whose ability to degrade dewaxed cotton, but not Avicel cellulose, was lost following initial isolation in the variant 007S. The ability was recovered after serial subculture to give the cotton-degrading strain 007C. This has allowed us to investigate the factors required for degradation of this particularly recalcitrant form of cellulose.
The major proteins associated with the bacterial cell surface and with the culture supernatant were analyzed for R. flavefaciens 007S and 007C grown with cellobiose, xylan or Avicel cellulose as energy sources. Identification of the proteins was enabled by a draft genome sequence obtained for 007C. Among supernatant proteins a cellulosomal GH48 hydrolase, a rubrerthyrin-like protein and a protein with type IV pili N-terminal domain were the most strongly up-regulated in 007C cultures grown on Avicel compared with cellobiose. Strain 007S also showed substrate-related changes, but supernatant expression of the Pil protein and rubrerythrin in particular were markedly lower in 007S than in 007C during growth on Avicel.
This study provides new information on the extracellular proteome of R. flavefaciens and its regulation in response to different growth substrates. Furthermore it suggests that the cotton cellulose non-degrading strain (007S) has altered regulation of multiple proteins that may be required for breakdown of cotton cellulose. One of these, the type IV pilus was previously shown to play a role in adhesion to cellulose in R. albus, and a related pilin protein was identified here for the first time as a major extracellular protein in R. flavefaciens.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
In this study anaerobic digestion of selected lignocellulosic substrate, namely brewery spent grain (BSG), was studied. In order to facilitate anaerobic digestion several types of pretreatment ...methods were tested such as: mechanical, chemical (alkali and acid) and thermo-chemical. The anaerobic digestion experiments were carried out in a semi-continuous stirred bioreactors with the organic loading rates between 2.9 and 3.9 kgCOD m-3 d-1 (1.9 and 2.5 kgVSS m-3 d-1 respectively) and corresponding hydraulic retention times of 33-39 days. Biogas production and composition, pH, COD, TSS and VSS, short chain fatty acids and phenolic compounds were measured. A significant inhibition of biogas production occurred, depending on the type of substrate pretreatment. There are indications that p-cresol is responsible for process inhibition when its concentration in the reaction mixture exceeds critical value between 115 and 240 mg L-1. Anaerobic digestion of chemically pretreated BSG (acid and alkali) and untreated-raw BSG was inhibited between the days 56 and 63 of the experiment, followed by thermo-chemically pretreated BSG on day 112 and mechanically pretreated BSG on day 126. Analyses of the substrates showed no phenolic compounds either in raw-untreated BSG or pretreated substrates, therefore the recorded p-cresol is an intermediate degradation product, responsible for process inhibition.
In this perspective analysis, we strive to answer the following question: how can we advance integrative biology research in the 21st century with lessons from animal science? At the University of ...Ljubljana, Biotechnical Faculty, Department of Animal Science, we share here our three lessons learned in the two decades from 2002 to 2022 that we believe could inform integrative biology, systems science, and animal science scholarship in other countries and geographies. Cultivating multiomics knowledge through a conceptual lens of integrative biology is crucial for life sciences research that can stand the test of diverse biological, clinical, and ecological contexts. Moreover, in an era of the current COVID-19 pandemic, animal nutrition and animal science, and the study of their interactions with human health (and vice versa) through integrative biology approaches hold enormous prospects and significance for systems medicine and ecosystem health.
Cellulose is the main structural component of plant cell wall and thus the most abundant carbohydrate in nature. However, extracting the energy from this abundant source is limited by its ...recalcitrant nature. The hydrolysis of plant cell wall requires synergystic action of different enzymes, including multiple cellulases, hemicellulases, pectinases, etc. Meanwhile aerobic cellulolytic microorganisms release large quantities of synergistically acting free enzymes in their environment, most anaerobic microorganisms evolved more efficient strategies to optimize the process of plant cell wall degradation, for example production of extracellular multi-enzyme complexes (cellulosomes). Cellulosomes consist of at least one core structural protein, named scaffoldin, which firmly binds numerous enzymatic subunits, and usually also plays a major role in substrate binding. Although the general structure of cellulosomes seems universal, differences in number and identity of complex components do exist among microorganisms. The article surveys the current knowledge about cellulosomes, focusing on three best investigated cellulolytic clostridia, one representative of ruminal bacteria and novel findings concerning anaerobic fungi. Efforts in construction of artificially engineered cellulosomal systems (designer cellulosomes) as well as their biotechnological potential are also discussed.
The expression of Ruminococcus flavefaciens 007S cellulases in different incubation time points (growth stages) and their substrate inducibility were analyzed by comparing the zymogram expression ...profiles of cultures grown on insoluble cellulose (Avicel) with cellobiose-grown cultures. The molecular weights of the enzymes were compared to (putative) cellulases encoded in the R. flavefaciens FD-1 genome.
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