313 research outputs found
Fructooligosaccharide production by Penicillium expansum
Fructooligosaccharides (FOS) production
by Penicillium expansum was evaluated. In a first
stage, the best conditions for P. expansum growth and
sporulation were established with potato/dextrose/
agar being the most suitable medium at between 22
and 25°C, giving good growth and good sporulation.
The inocula from this medium were used for FOS
production using shake-flask cultures, and yielded
0.58 g FOS/g sucrose (3.25 g FOS/l.h), demonstrating
the potential of this strain for sucrose conversion
to FOS.Fundação para a Ciência e a Tecnologia (FCT) - SFRH/BPD/38212/200
The influence of initial xylose concentration, agitation, and aeration on ethanol production by Pichia stipitis from rice straw hemicellulosic hydrolysate
Rice straw hemicellulosic hydrolysate was used as fermentation medium for ethanol production by Pichia stipitis NRRL Y-7124. Shaking bath experiments were initially performed aiming to establish the best initial xylose concentration to be used in this bioconversion process. In the sequence, assays were carried out under different agitation (100 to 200 rpm) and aeration (V flask/V medium ratio varying from 2.5 to 5.0) conditions, and the influence of these variables on the fermentative parameters values (ethanol yield factor, Y P/S; cell yield factor, Y X/S; and ethanol volumetric productivity, Q P) was investigated through a 22 full-factorial design. Initial xylose concentration of about 50 g/l was the most suitable for the development of this process, since the yeast was able to convert substrate in product with high efficiency. The factorial design assays showed a strong influence of both process variables in all the evaluated responses. The agitation and aeration increase caused a deviation in the yeast metabolism from ethanol to biomass production. The best results (Y P/S = 0.37 g/g and Q P = 0.39 g/l.h) were found when the lowest aeration (2.5 V flask/V medium ratio) and highest agitation (200 rpm) levels were employed. Under this condition, a process efficiency of 72.5% was achieved. These results demonstrated that the establishment of adequate conditions of aeration is of great relevance to improve the ethanol production from xylose by Pichia stipitis, using rice straw hemicellulosic hydrolysate as fermentation medium.The financial support from Fapesp (Brazil) is gratefully acknowledged
Production of fructooligosaccharides and b-fructofuranosidase by batch and repeated batch fermentation with immobilized cells of Penicillium expansum
The production of fructooligosaccharides
(FOS) and b-fructofuranosidase (FFase) by immobilized
cells of Penicillium expansum was evaluated. In an initial
stage, different low-cost materials including synthetic fiber,
polyurethane foam, stainless steel sponge, loofah sponge,
and cork oak were tested as carrier for the fungus immobilization.
Additionally, the influence of the inoculum age
(1 or 3 weeks) on cells immobilization, FOS and FFase
production was also verified. Synthetic fiber and polyurethane
foam were the best materials for P. expansum
immobilization (2.21 and 1.98 g/g carrier, respectively)
and FOS production (120.3 and 104.8 g/l), and gave also
high results of FFase activity (23.01 and 32.42 U/ml).
Then, the production of FOS and FFase by repeated batch
fermentation with P. expansum immobilized on synthetic
fiber was studied, aiming to improve the batch fermentation
results. The results obtained in this stage were very
promising with FOS yields of 87, 72, and 44 %, in the 3
initial cycles (60 h), respectively; the FFase activity was
constant throughout the process (6 cycles, 96 h). Repeated
batch fermentation with immobilized cells of P. expansum
was found as being a technology with great potential for
FOS and FFase production on industrial scaleThe financial support from FCT, the Portuguese Foundation for Science and Technology (research grant SFRH/BPD/38212/2007) is gratefully acknowledged
Comprehensive assessment of spatter material generated during selective laser melting of stainless steel
Laser-powder interaction and meltpool dynamics govern the physics behind the selective laser melting process. Spattering is an unavoidable phenomenon taking place during the process which is known to influence the integrity of the interaction between the incident laser beam and change the powder bed characteristics. This can consequently have a negative effect on final part integrity and quality of recycled powder. Hence, it is crucial to assess the characteristics of spatter particles to avoid the printing of defective parts. This work reports a detailed characterisation of spatter matter generated during selective laser melting of stainless steel. To better assess the characteristics of the spatter, the spattered material was benchmarked against the virgin powder. The results show no microstructural differences. However, the spatter morphological, chemical, optical and physical properties assessed in this work differ from the virgin powder. The results presented in this work are of significant contribution to the powder bed fusion field of additive manufacturing as it provides a unique insight to the characteristics of spatter matter generated from the processing of 316L stainless steel powde
Fucoidan-degrading fungal strains: screening, morphometric evaluation, and influence of medium composition
Ten different fungal strains from the genus Aspergillus, Penicillium, and Mucor
were screened for fucoidan hydrolyzing ability aiming to find microorganisms able to
produce sulfated fucan-degrading enzymes. Screening was carried out by measuring the
strains kinetic and morphometric behavior over plate assays using Laminaria japonica
fucoidan as only carbon source, testing three nitrogen sources (urea, peptone, and sodium
nitrate). The selected fungal strains were subsequently used in submerged fermentations,
which were performed for (1) selection of the strains able to growth over fucoidan medium
and (2) media selection, testing the synergy of fucoidan with other sugars for inducing high
enzyme titles. Radial expansion and hyphae parameters were observed for Aspergillus niger
PSH, Mucor sp. 3P, and Penicillium purpurogenum GH2 grown only over fucoidan-urea
medium. A. niger PSH showed the maximum enzymatic activity values, which were
significantly different (p<0.05) from those achieved by the other selected fungi. Sucrose
addition to fucoidan media proportioned the highest fucoidanase activity values for this
fungal strain. This research allowed establishing optimal conditions for metabolites
synthesis by fungal stains able to act toward fucoidan ramified matrix.Mexican
Science and Technology Council (CONACYT
An overview of the recent developments on fructooligosaccharide production and applications
Over the past years, many researchers have suggested
that deficiencies in the diet can lead to disease states
and that some diseases can be avoided through an adequate
intake of relevant dietary components. Recently, a great interest
in dietary modulation of the human gut has been registered.
Prebiotics, such as fructooligosaccharides (FOS), play a key
role in the improvement of gut microbiota balance and in
individual health. FOS are generally used as components of
functional foods, are generally regarded as safe (generally
recognized as safe status—from the Food and Drug Administration,
USA), and worth about 150€ per kilogram. Due to
their nutrition- and health-relevant properties, such as moderate
sweetness, low carcinogenicity, low calorimetric value,
and low glycemic index, FOS have been increasingly used
by the food industry. Conventionally, FOS are produced
through a two-stage process that requires an enzyme production
and purification step in order to proceed with the chemical
reaction itself. Several studies have been conducted on the
production of FOS, aiming its optimization toward the development
of more efficient production processes and their potential
as food ingredients. The improvement of FOS yield and
productivity can be achieved by the use of different fermentative
methods and different microbial sources of FOS producing
enzymes and the optimization of nutritional and
culture parameter; therefore, this review focuses on the latest
progresses in FOS research such as its production, functional
properties, and market data.Agencia de Inovacao (AdI)-Project BIOLIFE reference PRIME 03/347. Ana Dominguez acknowledges Fundacao para a Ciencia e a Tecnologia, Portugal, for her PhD grant reference SFRH/BD/23083/2005
Life cycle assessment of bacterial cellulose production
Purpose
Bacterial cellulose (BC), obtained by fermentation, is an innovative and promising material with a broad spectrum of potential applications. Despite the increasing efforts towards its industrialization, a deeper understanding of the environmental impact related to the BC production process is still required. This work aimed at quantifying the environmental, health, and resource depletion impacts related to a production of BC.
Methods
An attributional life cycle assessment (LCA) was applied to a process design of production of BC, by static culture, following a cradle-to-gate approach. The LCA was modeled with GaBi Pro Software using the ReCiPe 2016 (H) methodology with environmental impact indicators at midpoint level. The functional unit was defined as 1 kg of BC (dry mass), in 138.8 kg of water.
Results
From the total used resources (38.9 ton/kg of BC), water is the main one (36.1 ton/kg of BC), most of which (98%) is returned to fresh waters after treatment. The production of raw materials consumed 17.8 ton of water/kg of BC, 13.8 ton/kg of BC of which was for the production of carton packaging, culture medium raw materials, and sodium hydroxide (for the washing of BC). The remaining consumed water was mainly for the fermentation (3.9 ton/kg) and downstream process (7.7 ton/kg). From the identified potential environmental impacts, the production of raw materials had the highest impact, mainly on Climate change, Fossil depletion, Human toxicity, non-cancer, and Terrestrial toxicity. The sodium dihydrogen phosphate production, used in the culture medium, showed the highest environmental impacts in Human toxicity, non-cancer and Terrestrial ecotoxicity, followed by corn syrup and carton production. The static culture fermentation and downstream process showed impact in Climate change and Fossil depletion.
Conclusions
Per se, the BC production process had a small contribution to the consumption of resources and environmental impact of the BC global life cycle.This study was supported by the Portuguese Foundation
for Science and Technology (FCT) within the scope of the strate gic funding of UIDB/04469/2020 and UIDB/00511/2020 units and
MultiBiorefinery project (SAICTPAC/0040/2015-POCI-01-0145-
FEDER-016403). This study was also supported by The Navigator
Company through the I&D no. 21874, “Inpactus-–Produtos e Tecno logias Inovadores a partir do Eucalipto”, funded through the European
Regional Development Fund (ERDF) and the Programa Operacional
Competitividade e Internacionalização (POCI) is greatly acknowl edged. The work by Belmira Neto was fnancially supported by Base
Funding—UIDB/00511/2020 of the Laboratory for Process Engineer ing, Environment, Biotechnology and Energy—LEPABE—funded by
national funds through the FCT/MCTES (PIDDAC).info:eu-repo/semantics/publishedVersio
Hypoplastic Left Heart Syndrome Current Considerations and Expectations
In the recent era, no congenital heart defect has undergone a more dramatic change in diagnostic approach, management, and outcomes than hypoplastic left heart syndrome (HLHS). During this time, survival to the age of 5 years (including Fontan) has ranged from 50% to 69%, but current expectations are that 70% of newborns born today with HLHS may reach adulthood. Although the 3-stage treatment approach to HLHS is now well founded, there is significant variation among centers. In this white paper, we present the current state of the art in our understanding and treatment of HLHS during the stages of care: 1) pre-Stage I: fetal and neonatal assessment and management; 2) Stage I: perioperative care, interstage monitoring, and management strategies; 3) Stage II: surgeries; 4) Stage III: Fontan surgery; and 5) long-term follow-up. Issues surrounding the genetics of HLHS, developmental outcomes, and quality of life are addressed in addition to the many other considerations for caring for this group of complex patients
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