Quantification of extracellular proteases and chitinases from marine bacteria

A total of 92 marine bacteria belonging to Pseudomonas, Pseudoalteromonas, Psychrobacter, and Shewanella were first screened for their proteolytic activity. In total, four Pseudomonas strains belonging to Ps. fluorescens, Ps. fragi, Ps. gessardii, and Ps. marginalis; 14 Pseudoalteromonas strains belonging to Psa. arctica, Psa. carrageenovora, Psa. elyakovii, Psa. issachenkonii, Psa. rubra, Psa. translucida, and Psa. tunicata; and two Shewanella strains belonging to S. baltica and S. putrefaciens were identified to have a weak to high proteolytic activity (from 478 to 4445 mU/mg trypsin equivalent) against skim milk casein as protein source. Further chitinolytic activity screening based on these 20 proteolytic strains using colloidal chitin yielded five positive strains which were tested against three different chitin substrates in order to determine the various types of chitinases. Among the strains that can produce both proteases and chitinases, Psa. rubra DSM 6842T expressed not only the highest proteolytic activity (2558 mU/mg trypsin equivalent) but also the highest activity of exochitinases, specifically, β-N-acetylglucosaminidase (6.33 mU/107 cfu) as well. We anticipate that this strain can be innovatively applied to the valorization of marine crustaceans side streams

Sensitive and specific detection of E. coli using biomimetic receptors in combination with a modified heat-transfer method

We report on a novel biomimetic sensor that allows sensitive and specific detection of Escherichia colt (E. coli) bacteria in a broad concentration range from 10(2) up to 10(6) CFU/mL in both buffer fluids and relevant food samples (i.e. apple juice). The receptors are surface-imprinted polyurethane layers deposited on stainless-steel chips. Regarding the transducer principle, the sensor measures the increase in thermal resistance between the chip and the liquid due to the presence of bacteria captured on the receptor surface. The low noise level that enables the low detection limit originates from a planar meander element that serves as both a heater and a temperature sensor. Furthermore, the experiments show that the presence of bacteria in a liquid enhances the thermal conductivity of the liquid itself. Reference tests with a set of other representative species of Enterobacteriaceae, closely related to E. coli, indicate a very low cross-sensitivity with a sensor response at or below the noise level

Aptamer-based extraction of ergot alkaloids from ergot contaminated rye feed

Ergot alkaloids are mycotoxins which can be found in food based on cereal-crops, due to a contamination of plants by fungi of the genus Claviceps. The ingestion of ergot contaminated cereal crops can lead to a severe poisoning known as ergotism. For food and feed safety purposes, the extraction of ergot alkaloids from ergot contaminated flour was investigated. For the specific recognition of ergot alkaloids, DNA aptamer ligands specially selected for ergot alkaloids were grafted onto silica gel in order to construct a specific solid phase extraction system. The aptamer-functionalized silica gels were used to extract ergot alkaloids from a contaminated rye feed sample. The presence of ergot alkaloids eluted from the aptamer-functionalized silica gels was analyzed using LC-QTOF-MS. By using this simple system, it was possible to specifically extract ergosine, ergokryptine and ergocornine from an ergot contaminated rye feed sample. This aptamer-based extraction tool shows the applicability of aptamers for the specific extraction of toxins or natural compounds from turbid matrices in a one-step procedure

Chemically versus thermally processed brown shrimp shells or Chinese mitten crab as a source of chitin, nutrients or salts and as microbial stimulant in soilless strawberry cultivation

Brown shrimp (Crangon crangon) shells and Chinese mitten crab (Efiocheir sinensis) were chemically demineralized and deproteinized (denoted as M1 to M4 for the shrimp shells and MS to M7 for the Chinese mitten crab), and shrimp shells were torrefied at 200 to 300 degrees C (denoted as R200, R255, R300), and were compared with a commercially available chitin source (denoted as reference chitin). Based on their chemical characteristics, a selection of chitin sources was tested for their N mineralization capacity. The N release was high for the chemically treated shrimp shells and Chinese mitten crab, but not for the Dandled shrimp shells with or without acid treatment, indicating that treatment at 200 et or higher resulted in low N availability. Interaction with nutrients was tested in a leaching experiment with limed peat for three thermally and two chemically processed shrimp shells and the reference chitin source. The K concentrations in the leachate for the chemically treated shrimp shells and the reference chitin were lower than for limed peat during fertigation. Irreversible K retention was observed for one source of chemically treated shrimp shells, and the reference chitin. The thermally treated shrimp shells had a significantly higher net release of P. Na and CI than the treatment without chitin source. Three shrimp shell based materials (M4, R200 and 8300) and the reference chitin were tested in a greenhouse trial with strawberry at a dose of 2 g/L limed peat. A very positive and significant effect on Borryris cinerea disease suppression in the leaves was found for the reference chitin, M4 and R200 compared to the unamended control. The disease suppression of the 3 chitin sources was linked with an increase of the microbial biomass in the limed peat with 24% to 28% due to chitin decomposition and a 9-44% higher N uptake in the plants

A new tool for faster construction of marine biotechnology collaborative networks.

The increasing and rapid development in technologies, infrastructures, computational power, data availability and information flow has enabled rapid scientific advances. These entail transdisciplinary collaborations that maximize sharing of data and knowledge and, consequently, results, and possible technology transfer. However, in emerging scientific fields it is sometimes difficult to provide all necessary expertise within existing collaborative circles. This is especially true for marine biotechnology that directly addresses global societal challenges. This article describes the creation of a platform dedicated to facilitating the formation of short or mid-term collaborative networks in marine biotechnology. This online platform (https://www.ocean4biotech.eu/map/) enables experts (researchers and members of the marine biotechnology community in general) to have the possibility to showcase their expertise with the aim of being integrated into new collaborations/consortia on the one hand, or to use it as a search tool to complement the expertise in planned/running collaborations, on the other. The platform was created within the Ocean4Biotech (European transdisciplinary networking platform for marine biotechnology) Action, funded under the framework of the European Cooperation in Science and Technology (COST). To build the platform, an inquiry was developed to identify experts in marine biotechnology and its adjunct fields, to define their expertise, to highlight their infrastructures and facilities and to pinpoint the main bottlenecks in this field. The inquiry was open to all experts in the broad field of marine biotechnology, including non-members of the consortium. The inquiry (https://ee.kobotoolbox.org/single/UKVsBNtD) remains open for insertion of additional expertise and the resulting interactive map can be used as a display and search tool for establishing new collaborations

Valorisation of crustacean and bivalve processing side streams for industrial fast time-to-market products: A review from the European Union regulation perspective

A massive amount of crustaceans and bivalves are consumed each year, leading to millions of tons of processing side streams from the seafood industry. Considering the current trend of (bio)circular and zero-waste food production, crustacean and bivalve processing side streams (CBPS) seem a promising and emerging resource for producing high-value-added products. This paper highlights the general composition of CBPS with high commercial values, namely, protein, lipids, carotenoids, minerals and chitins. The extraction strategies of these fractions, including conventional chemical and environmentally friendly methods, are also discussed. This review presents and summarises CBPS as raw materials for developing fast time-to-market products complying with specific EU regulations, including animal feeds, bio-pesticide/stimulants, and cosmetic ingredients. This paper also provides insights into challenges of applying CBPS as raw materials to generate products for human consumption