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