| 1. |
- Capecchi, Lorenzo, et al.
(författare)
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Combined ethanol and methane production from switchgrass (Panicum virgatum L.) impregnated with lime prior to steam explosion
- 2016
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Ingår i: Biomass & Bioenergy. - : Elsevier BV. - 0961-9534. ; 90, s. 22-31
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Tidskriftsartikel (refereegranskat)abstract
- Pretreatments are crucial to achieve efficient conversion of lignocellulosic biomass to soluble sugars. In this light, switchgrass was subjected to 13 pretreatments including steam explosion alone (195 °C for 5, 10 and 15 min) and after impregnation with the following catalysts: Ca(OH)2 at low (0.4%) and high (0.7%) concentration; Ca(OH)2 at high concentration and higher temperature (205 °C for 5, 10 and 15 min); H2SO4 (0.2% at 195 °C for 10 min) as reference acid catalyst before steam explosion. Enzymatic hydrolysis was carried out to assess pretreatment efficiency in both solid and liquid fraction. Thereafter, in selected pretreatments the solid fraction was subjected to simultaneous saccharification and fermentation (SSF), while the liquid fraction underwent anaerobic digestion (AD). Lignin removal was lowest (12%) and highest (35%) with steam alone and 0.7% lime, respectively. In general, higher cellulose degradation and lower hemicellulose hydrolysis were observed in this study compared to others, depending on lower biomass hydration during steam explosion. Mild lime addition (0.4% at 195 °C) enhanced ethanol in SSF (+28% than steam alone), while H2SO4 boosted methane in AD (+110%). However, methane represented a lesser component in combined energy yield (ethanol, methane and energy content of residual solid). Mild lime addition was also shown less aggressive and secured more residual solid after SSF, resulting in higher energy yield per unit raw biomass. Decreased water consumption, avoidance of toxic compounds in downstream effluents, and post process recovery of Ca(OH)2 as CaCO3 represent further advantages of pretreatments involving mild lime addition before steam explosion.
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| 2. |
- Modesto, Monica, et al.
(författare)
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Bifidobacterium callitrichidarum sp. nov. from the faeces of the emperor tamarin (Saguinus imperator)
- 2018
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Ingår i: International Journal of Systematic and Evolutionary Microbiology. - : Microbiology Society. - 1466-5034 .- 1466-5026. ; 68:1, s. 141-148
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Tidskriftsartikel (refereegranskat)abstract
- Three Gram-stain-positive, non-spore-forming, microaerophilic and fructose-6-phosphate phosphoketolase positive strains were isolated from a faecal sample of an adult subject of the emperor tamarin (Saguinus imperator). Given that the isolates revealed identical BOX PCR profiles, strain TRI 5T was selected as a representative and characterized further. Comparative analysis of 16S rRNA gene sequence similarity revealed that strain TRI 5T was closely related to Bifidobacterium saguini DSM 23967T (96.4 %) and to Bifidobacterium longum subsp. longum ATCC 15708 (96.2 %). Multilocus sequence analyses of five housekeeping genes showed the close phylogenetic relatedness of this strain to Bifidobacterium breve DSM 20213T (hsp60 94.1 %), Bifidobacterium saguini DSM 23967T (clpC 91 %), Bifidobacterium avesanii DSM 100685T (dnaG 80.3 %), Bifidobacterium longum subsp. infantis ATCC 15697T (dnaJ 85.3 %) and Bifidobacterium longum subsp. longum ATCC 15708 (rpoB 93 %), respectively. The peptidoglycan type was A3β, with an interpeptide bridge comprising L-Orn (Lys) – L-Ser – L-Ala – L-Thr – LAla. The DNA G+C content of strain TRI 5T was 60.9 mol%. Based on the data provided, strain TRI 5T represents a novel species of the genus Bifidobacterium for which the name Bifidobacterium callitrichidarum sp. nov. is proposed. The type strain is TRI 5T (=DSM 103152T=JCM 31790T).
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| 3. |
- Olofsson, Tobias C., et al.
(författare)
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Bifidobacterium mellis sp. nov., isolated from the honey stomach of the honey bee Apis mellifera
- 2023
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Ingår i: International Journal of Systematic and Evolutionary Microbiology. - : Microbiology Society. - 1466-5026 .- 1466-5034. ; 73:3
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Tidskriftsartikel (refereegranskat)abstract
- A novel Bifidobacterium strain, Bin7NT, was isolated from the honey stomach of the honey bee Apis mellifera. Cells are Gram-positive, non-motile, non-sporulating, facultative anaerobic and fructose 6-phosphate phosphoketolase-positive. Their optimal growth is at 37 °C in anaerobiosis in MRS (De Man, Rogosa and Sharpe) added with cysteine. The honey bee microbiota was composed of several phylotypes of Bifidobacterium and Lactobacillus. Comparative analysis of 16S rRNA gene sequence similarity revealed that strain Bin7NT grouped with Bifidobacterium species originating from honey bees and was closely related to Bifidobacterium asteroides DSM 20089T (99.67 % similarity). However, the highest average nucleotide identity and digital DNA– DNA hybridization values of 94.88 and 60.6 %, respectively, were obtained with Bifidobacterium choladohabitans JCM 34586T. The DNA G+C content of the type strain is 60.8 mol%. The cell-wall peptidoglycan is of the A4β l-Orn–d-Asp type. The main cellular fatty acids of strain Bin7NT are C18: 1 ω9c, C16: 0, C18: 1 ω7c and C18: 0. Phenotypic characterization and genotyping based on the genome sequences clearly show that this strain is distinct from the type strains of the so far recognized Bifidobacterium species. Thus, Bifidobacterium mellis sp. nov. (Bin7NT=DSM 29108T=CCUG 66113T) is proposed as novel Bifidobacterium species.
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| 4. |
- Olofsson, Tobias, et al.
(författare)
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Honeybee-Specific Bifidobacteria and Lactobacilli
- 2017
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Ingår i: The Bifidobacteria and Related Organisms : Biology, Taxonomy, Applications - Biology, Taxonomy, Applications. - 9780128050606 ; , s. 235-241
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Bokkapitel (refereegranskat)abstract
- Honeybees are one of our most important insects, not only for their pollination services but also for their production of honey. Honey is the main food for honeybees, produced from collected nectars and transported to the hive. Humans have consumed this mysterious food and applied it since ancient times in traditional medicine around the world. In 2005 we discovered an unknown key to honeybees’ health and to honey production, which was the presence of previously unknown species of lactobacilli and bifidobacteria. These bacterial species are constant in all honeybees and present in large amounts in fresh honey originating in all continents. They work synergistically to defend their host against microbial incoming threats introduced by nectar foraging and end up in newly produced honey through detaching from the honey stomach. Our research has shown that these beneficial symbiotic bacteria possess antimicrobial characteristics and produce a myriad of bioactive metabolites that protect honeybees against pathogens and explain honeys’ therapeutically significant properties, known by humans since ancient times. Therefore, understanding of the mechanisms of action behind these characteristics through genomic and proteomic studies are crucial in order to find future alternative to antibiotics. In this chapter we discuss the importance of these microbiota in honeybee health and the traditional medicine that is honey with focus on future perspectives.
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| 5. |
- Patrignani, Francesca, et al.
(författare)
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Technological potential of Bifidobacterium aesculapii strains for fermented soymilk production
- 2018
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Ingår i: LWT - Food Science and Technology. - : Elsevier BV. - 1096-1127 .- 0023-6438. ; 89, s. 689-696
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Tidskriftsartikel (refereegranskat)abstract
- The present research was aimed to investigate the technological potentialities of seven strains of Bifidobacterium aesculapii, a species recently described, in terms of exopolysaccharide (EPS) production and as starter fermentation in soybean milk. The strain production of EPS was firstly evaluated in model system, using different carbon sources. Furthermore, the fermented products obtained by the seven strains of B. aesculapii were tested for their EPS content and strain cell loads, the volatile molecule profiles, the texture features and the overall acceptance. The data showed that all the B. aesculapii strains were able to produce EPS in vitro model in presence of 1.5% and 2% glucose while only four strains were able to produce EPS in presence of lactose 2%. When the strains were employed as fermentation starters in soybean milk, some showed a good growth potential, fermenting the substrate in 14 h and giving rise to fermented products with good firmness and viscosity indexes. Moreover, five strains out seven showed production of EPS (from 5 to 174 μg/mL) in soybean fermented milk.
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| 6. |
- Qvirist, Linnea, 1987, et al.
(författare)
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Isolation, identification and characterization of yeasts from fermented goat milk of the Yaghnob Valley in Tajikistan
- 2016
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Ingår i: Frontiers in Microbiology. - : Frontiers Media SA. - 1664-302X. ; 7:1690
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Tidskriftsartikel (refereegranskat)abstract
- The geographically isolated region of the Yaghnob Valley, Tajikistan, has allowed its inhabitants to maintain a unique culture and lifestyle. Their fermented goat milk constitutes one of the staple foods for the Yaghnob population, and is produced by backslopping, i.e., using the previous fermentation batch to inoculate the new one. This study addresses the yeast composition of the fermented milk, assessing genotypic, and phenotypic properties. The 52 isolates included in this study revealed small species diversity, belonging to Kluyveromyces marxianus, Pichia fermentans, Saccharomyces cerevisiae, and one Kazachstania unispora. The K. marxianus strains showed two different genotypes, one of which never described previously. The two genetically different groups also differed significantly in several phenotypic characteristics, such as tolerance toward high temperatures, low pH, and presence of acid. Microsatellite analysis of the S. cerevisiae strains from this study, compared to 350 previously described strains, attributed the Yaghnobi S. cerevisiae to two different ancestry origins, both distinct from the wine and beer strains, and similar to strains isolated from human and insects feces, suggesting a peculiar origin of these strains, and the existence of a gut reservoir for S. cerevisiae. Our work constitutes a foundation for strain selection for future applications as starter cultures in food fermentations. This work is the first ever on yeast diversity from fermented milk of the previously unexplored area of the Yaghnob Valley.
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