14,874 research outputs found
Biosurfactants – potential and applications
Biosurfactants are molecules that exhibit pronounced surface and emulsifying activities, produced by a
variety of microorganisms. A host of interesting features of biosurfactants, such as higher
biodegradability, lower toxicity, and effectiveness at extremes of temperature, pH and salinity; have
led to a wide range of potential applications in the fields of oil recovery, environmental bioremediation,
food processing and medicine. In spite of the immense potential of biosurfactants, their use still
remains limited, possibly due to their high production and extraction costs, low yields in production
processes and lack of information on their toxicity towards human systems [1]. The use and potential
commercial application of biosurfactants in the medical field has increased during the past decade [2].
Their antibacterial, antifungal and antiviral activities make them relevant molecules for applications in
combating many diseases and as therapeutic agents. In addition their role as anti-adhesive agents
against several pathogens indicates their utility as suitable anti-adhesive coating agents for medical
insertional materials leading to a reduction of a large number of hospital infections without the use of
synthetic drugs and chemicals. The most promising alternative to turn its production competitive for
industrial applications is the knowledge of the genes involved in their biosynthesis. Identification and
isolation of those genes will allow enhanced production. Furthermore, modification of those genes by
genetic engineering will result in the production of novel biosurfactants with specific novel properties.
Medicinal and therapeutic perspectives of biosurfactants applications and future research plans will be
presented
Melhoramento genético, registro e proteção de cultivares de Coffea canephora para o Estado de Rondônia.
O melhoramento genético do Coffea canephora objetivando a seleção de genótipos de ‘Conilon’ e ‘Robusta’ mais produtivos, tolerantes aos principais patógenos e adaptados às condições edafoclimáticas da região é de grande importância para impactar a cadeia produtiva do café no Estado de Rondônia. Tão importante quanto a obtenção da cultivar, é o seu registro e/ou proteção. Todas essas etapas fazem parte do processo de desenvolvimento e lançamento da cultivar, para que a mesma seja disponibilizada aos agricultores.bitstream/item/57882/1/doc143-cafe.pd
Biosurfactants production from cheese whey
Biosurfactants are molecules that exhibit
pronounced surface and emulsifying activities,
produced by a variety of microorganisms. A host of
interesting features of biosurfactants, such as higher
biodegradability, lower toxicity, and effectiveness at
extremes of temperature, pH and salinity; have led to
a wide range of potential applications in the fields
of oil recovery, environmental bioremediation, food
processing and medicine. In spite of the immense
potential of biosurfactants, their use still remains
limited, mainly due to their high production and
extraction costs, low yields in production processes and lack of information on their toxicity towards human systems. However, the
use of cheaper substrates and optimal growth and production conditions
coupled with novel and efficient multistep downstream processing methods and
the use of recombinant and mutant hyper producing microbial strains can
make biosurfactant production economically feasible. Often, the amount and
type of a raw material can contribute considerably to the production cost; it is
estimated that raw materials account for 10 to 30% of the total production
costs in most biotechnological processes. Thus, to reduce this cost it is
desirable to use low-cost raw materials. One possibility explored extensively is
the use of cheap and agro-based raw materials as substrates for biosurfactant
production. A variety of cheap raw materials, including plant-derived oils, oil
wastes, starchy substances, cheese whey and distillery wastes have been
reported to support biosurfactant production. Future biosurfactant research
should, therefore, be more focused on the economics of biosurfactant
production processes, particularly through the use of alternative low-cost
fermentative media. This review looks at the future perspectives of large-scale
profitable production of biosurfactants
Reproduction and food habits of the lined seahorse, Hippocampus erectus (Teleostei: Syngnathidae) of Chesapeake Bay, Virginia.
The reproductive and feeding biology of the lined seahorse, Hippocampus erectus, was studied inChesapeake Bay. Seahorses are monogamous, and males incubate the eggs received from femalesin a closed brood pouch (= marsupium). Females do not play any parental care after mating. Totalsex ratio and the operational sex ratio was strongly skewed toward females. Males and females hadsimilar number of eggs/embryos and hydrated oocytes, respectively. The number of eggs/embryosfound in the male brood pouch varied from 97 to 1,552 (fish from 80 to 126 mm TL), whereas thenumber of hydrated oocytes in female varied from 90 to 1,313 (fish from 60 to 123 mm TL). Both,the number of eggs/embryos and hydrated oocytes were better linearly correlated to total weight thanto total length. The small snout and mouth size limits the feeding of the lined seahorse to small preysize. Amphypods were the predominant food items found in the guts, especially Ampithoe longimana,Gammarus mucronatus, and Caprella penantis. The lined seahorse is not abundant in ChesapeakeBay, but keeps a breeding population which is probably brought inside the bay by currents on driftingvegetation. Chances to find a partner may be difficult because of its low abundance, due to turbidwaters, and its sedentary behavior
Diagnosing numerical Cherenkov instabilities in relativistic plasma simulations based on general meshes
Numerical Cherenkov radiation (NCR) or instability is a detrimental effect
frequently found in electromagnetic particle-in-cell (EM-PIC) simulations
involving relativistic plasma beams. NCR is caused by spurious coupling between
electromagnetic-field modes and multiple beam resonances. This coupling may
result from the slow down of poorly-resolved waves due to numerical (grid)
dispersion and from aliasing mechanisms. NCR has been studied in the past for
finite-difference-based EM-PIC algorithms on regular (structured) meshes with
rectangular elements. In this work, we extend the analysis of NCR to
finite-element-based EM-PIC algorithms implemented on unstructured meshes. The
influence of different mesh element shapes and mesh layouts on NCR is studied.
Analytic predictions are compared against results from finite-element-based
EM-PIC simulations of relativistic plasma beams on various mesh types.Comment: 31 pages, 20 figure
Low-cost fermentative medium for biosurfactant production by Streptococcus thermophilus A
Interest in biosurfactants has increased considerably in recent years, as they are
potential candidates for many commercial applications in the petroleum,
pharmaceuticals, biomedical and food processing industries. Biosurfactants have several
advantages over chemical s urfactants including lower toxicity and higher
biodegradability, and effectiveness at extreme temperatures or pH values. In spite of the
advantages, fermentation must be cost competitive with chemical synthesis and many of
the potential applications that have been considered for biosurfactants depend on
whether they can be produced economically. The use of alternative molasses medium
(sucrose content 20 g/L, supplemented with 3 g/L yeast extract and 5 g/L peptone) for
biosurfactant production by Streptococcus thermophilus A was studied. Suitable models
were established to describe the response of the experiments pertaining to glucose or
sucrose consumption, cell growth and biosurfactant production. Conventional synthetic
M17 broth was used as control experiments. The replacement of M17 broth by cheaper
molasses medium resulted on an increase about 1.4 times in the mass of produced
biosurfactant (mg) per gram cell dry weight and a 80% medium preparation costs
reduction.In con clusion, the results obtained showed that molasses medium can be used
as a relatively inexpensive and economical alternative to conventional synthetic medium
for biosurfactant production by S. thermophilus A
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