Starch-Rich Microalgae as an Active Ingredient in Beer Brewing.

Microalgal biomass is widely studied for its possible application in food and human nutrition due to its multiple potential health benefits, and to address raising sustainability concerns. An interesting field whereby to further explore the application of microalgae is that of beer brewing, due to the capacity of some species to accumulate large amounts of starch under specific growth conditions. The marine species Tetraselmis chui is a well-known starch producer, and was selected in this study for the production of biomass to be explored as an active ingredient in beer brewing. Cultivation was performed under nitrogen deprivation in 250 L tubular photobioreactors, producing a biomass containing 50% starch. The properties of high-starch microalgal biomass in a traditional mashing process were then assessed to identify critical steps and challenges, test the efficiency of fermentable sugar release, and develop a protocol for small-scale brewing trials. Finally, T. chui was successfully integrated at a small scale into the brewing process as an active ingredient, producing microalgae-enriched beer containing up to 20% algal biomass. The addition of microalgae had a noticeable effect on the beer properties, resulting in a product with distinct sensory properties. Regulation of pH proved to be a key parameter in the process.

Patterns and roles of lignan and terpenoid accumulation in the reaction zone compartmentalizing pathogen-infected heartwood of Norway spruce.

MAIN CONCLUSION: Lignan impregnation of the reaction zone wood protects against oxidative degradation by fungi. Traumatic resin canals may play roles in the underlying signal transduction, synthesis, and translocation of defense compounds. Tree defense against xylem pathogens involves both constitutive and induced phenylpropanoids and terpenoids. The induced defenses include compartmentalization of compromised wood with a reaction zone (RZ) characterized by polyphenol deposition, whereas the role of terpenoids has remained poorly understood. To further elucidate the tree-pathogen interaction, we profiled spatial patterns in lignan (low-molecular-weight polyphenols) and terpenoid content in Norway spruce (Picea abies) trees showing heartwood colonization by the pathogenic white-rot fungus Heterobasidion parviporum. There was pronounced variation in the amount and composition of lignans between different xylem tissue zones of diseased and healthy trees. Intact RZ at basal stem regions, where colonization is the oldest, showed the highest level and diversity of these compounds. The antioxidant properties of lignans obviously hinder oxidative degradation of wood: RZ with lignans removed by extraction showed significantly higher mass loss than unextracted RZ when subjected to Fenton degradation. The reduced diversity and amount of lignans in pathogen-compromised RZ and decaying heartwood in comparison to intact RZ and healthy heartwood suggest that α-conindendrin isomer is an intermediate metabolite in lignan decomposition by H. parviporum. Diterpenes and diterpene alcohols constituted above 90% of the terpenes detected in sapwood of healthy and diseased trees. A significant finding was that traumatic resin canals, predominated by monoterpenes, were commonly associated with RZ. The findings clarify the roles and fate of lignan during wood decay and raise questions about the potential roles of terpenoids in signal transduction, synthesis, and translocation of defense compounds upon wood compartmentalization against decay fungi.

Retention and distribution of pesticides in planted filter microcosms designed for treatment of agricultural surface runoff.

Pesticides in agricultural surface water runoff cause a major threat to freshwater systems. Installation of filter systems or constructed wetlands in areas of preferential run-off is a possible measure for pesticides abatement. To develop such systems, combinations of filter materials suitable for retention of both hydrophilic and hydrophobic organic pesticides were tested for pesticide removal in planted microcosms. The retention of six pesticides frequently detected in surface waters (bentazone, MCPA, metalaxyl, propiconazole, pencycuron, and imidacloprid) was evaluated in unplanted and planted pot experiments with novel bed material mixtures consisting of pumice, vermiculite, water super-absorbent polymer (SAP) for retention of ionic and water soluble pesticides, and synthetic hydrophobic wool for adsorption of hydrophobic pesticides. The novel materials were compared to soil with high organic matter content. The highest retention of the pesticides was observed in the soil, with a considerable translocation of pesticides into the plants, and low leaching potential, in particular for the hydrophobic compounds. However, due to the high retention of pesticides in soil, environmental risks related to their long term mobilization cannot be excluded. Mixtures of pumice and vermiculite with SAP resulted in high retention of i) water and ii) both hydrophilic and hydrophobic pesticides but with much lower leaching potential compared to the mineral systems without SAP. Mixtures of such materials may provide near natural treatment options in riparian strips and also for treatment of rainwater runoff without the need for water containment systems.

Volatile Organic Compound Profiles From Wheat Diseases Are Pathogen-Specific and Can Be Exploited for Disease Classification.

Plants and fungi emit volatile organic compounds (VOCs) that are either constitutively produced or are produced in response to changes in their physico-chemical status. We hypothesized that these chemical signals could be utilized as diagnostic tools for plant diseases. VOCs from several common wheat pathogens in pure culture (Fusarium graminearum, Fusarium culmorum, Fusarium avenaceum, Fusarium poae, and Parastagonospora nodorum) were collected and compared among isolates of the same fungus, between pathogens from different species, and between pathogens causing different disease groups [Fusarium head blight (FHB) and Septoria nodorum blotch (SNB)]. In addition, we inoculated two wheat varieties with either F. graminearum or P. nodorum, while one variety was also inoculated with Blumeria graminis f.sp. tritici (powdery mildew, PM). VOCs were collected 7, 14, and 21 days after inoculation. Each fungal species in pure culture emitted a different VOC blend, and each isolate could be classified into its respective disease group based on VOCs with an accuracy of 71.4 and 84.2% for FHB and SNB, respectively. When all collection times were combined, the classification of the tested diseases was correct in 84 and 86% of all cases evaluated. Germacrene D and sativene, which were associated with FHB infection, and mellein and heptadecanone, which were associated with SNB infection, were consistently emitted by both wheat varieties. Wheat plants infected with PM emitted significant amounts of 1-octen-3-ol and 3,5,5-trimethyl-2-hexene. Our study suggests that VOC blends could be used to classify wheat diseases. This is the first step toward a real-time disease detection in the field based on chemical signatures of wheat diseases.

Uptake and elimination kinetics of the biocide triclosan and the synthetic musks galaxolide and tonalide in the earthworm Dendrobaena veneta when exposed to sewage sludge.

Sewage sludge is an important amendment that enriches soils with organic matter and provides plants with nutrients such as nitrogen and phosphorus. However, knowledge on the fate and effects of organic pollutants present in the sludge on soil organisms is limited. In the present study, the uptake of triclosan, galaxolide, and tonalide in the earthworm Dendrobaena veneta was measured 1 wk after amendment of agricultural soil with sewage sludge, while elimination kinetics were assessed over a 21-d period after transferring worms to clean soil. After 1-wk exposure, earthworms had accumulated 2.6 ± 0.6 µg g-1 galaxolide, 0.04 ± 0.02 µg g-1 tonalide, and 0.6 ± 0.2 µg g-1 triclosan. Both synthetic musks were efficiently excreted and below the limit of quantification after 3 and 14 d of depuration for tonalide and galaxolide, respectively. Triclosan concentrations, on the other hand, did not decrease significantly over the depuration period, which may lead to the transfer of triclosan in the food web. Environ Toxicol Chem 2017;36:2068-2073. © 2017 SETAC.

Analysis of non-cleaned QuEChERS extracts for the determination of pesticide residues in fruit, vegetables and cereals by gas chromatography-tandem mass spectrometry.

This paper investigated the possibility of leaving out the traditional clean-up step in the QuEChERS procedure and analysing non-cleaned extracts from fruit, vegetables and cereals with a combination of gas chromatography-tandem mass spectrometry (GC-MS/MS), back-flush technology and large-volume injection. By using calibration standards in cucumber matrix, recovery and precision were calculated in lettuce, orange and wheat for 109 pesticides at 0.01 and 0.1 mg kg(-1) in two sets of samples: one with and one without clean-up. For both spiking levels, 80-82% of the pesticides in the non-cleaned extracts and 80-84% of the pesticides in the cleaned extracts were within the acceptable recovery range of 70-120%. Precision data for both levels showed that 95% of the pesticides in the non-cleaned extracts and 93-95% of the pesticides in the cleaned extracts had RSDs below 20%. Recovery and precision data were determined using a two tailed t-test (p = 0.05). By using calibration standards in the respective matrix, we studied if the non-cleaned calibration standards gave an extra matrix effect compared with the cleaned standards by using the slope from calibration graphs and plotting the calculated extra matrix effect minus 100 for each compound. The results showed that for 79% of the pesticides, the extra matrix effect minus 100 was within the acceptable range of -20% to 20%. Five European Union proficiency tests on rye, mandarin, rice, pear and barley, respectively, from 2010 to 2012 were reanalysed omitting the clean-up step and showed satisfactory results. At least 70 injections of non-cleaned extracts were made without detecting any increased need for maintenance during the experimental period. Analysing non-cleaned QuEChERS extracts of lettuce, orange and wheat are possible under the conditions described in this paper because recovery, precision and specificity showed satisfactory results compared with samples subjected to traditional dispersive clean-up.

Habitat selection of a parasitoid mediated by volatiles informing on host and intraguild predator densities.

To locate and evaluate host patches before oviposition, parasitoids of herbivorous insects utilize plant volatiles and host-derived cues, but also evaluate predator-derived infochemicals to reduce predation risks. When foraging in host habitats infested with entomopathogenic fungi that can infect both a parasitoid and its host, parasitoids may reduce the risk of intraguild predation (IGP) by avoiding such patches. In this study, we examined whether the presence of the entomopathogenic fungi Metarhizium brunneum and Beauveria bassiana in soil habitats of a root herbivore, Delia radicum, affects the behavior of Trybliographa rapae, a parasitoid of D. radicum. Olfactometer bioassays revealed that T. rapae avoided fungal infested host habitats and that this was dependent on fungal species and density. In particular, the parasitoid avoided habitats with high densities of the more virulent fungus, M. brunneum. In addition, host density was found to be important for the attraction of T. rapae. Volatiles collected from host habitats revealed different compound profiles depending on fungal presence and density, which could explain the behavior of T. rapae. We conclude that T. rapae females may use volatile compounds to locate high densities of prey, but also compounds related to fungal presence to reduce the risk of IGP towards themselves and their offspring.

Olfactory cues from different plant species in host selection by female pea moths.

In herbivorous insects specialized on few plant species, attraction to host odor may be mediated by volatiles common to all host species, by specific compounds, or combinations of both. The pea moth Cydia nigricana is an important pest of the pea. Volatile signatures of four host plant species were studied to identify compounds involved in pea moth host selection and to improve previously reported attractive volatile blends. P. sativum and alternative Fabaceae host species were compared regarding female attraction, oviposition, and larval performance. Pea moth females were strongly attracted to the sweet pea Lathyrus odoratus, but larval performance on that species was moderate. Chemical analyses of sweet pea odor and electrophysiological responses of moth antennae led to identification of seven sweet-pea-specific compounds and ten compounds common to all tested host species. Blends of these specific and common cues were highly attractive to mated pea moth females in wind tunnel and field experiments.

Effects of picoxystrobin and 4-n-nonylphenol on soil microbial community structure and respiration activity.

There is widespread use of chemical amendments to meet the demands for increased productivity in agriculture. Potentially toxic compounds, single or in mixtures, are added to the soil medium on a regular basis, while the ecotoxicological risk assessment procedures mainly follow a chemical by chemical approach. Picoxystrobin is a fungicide that has caused concern due to studies showing potentially detrimental effects to soil fauna (earthworms), while negative effects on soil microbial activities (nitrification, respiration) are shown to be transient. Potential mixture situations with nonylphenol, a chemical frequently occurring as a contaminant in sewage sludge used for land application, infer a need to explore whether these chemicals in mixture could alter the potential effects of picoxystrobin on the soil microflora. The main objective of this study was to assess the effects of picoxystrobin and nonylphenol, as single chemicals and mixtures, on soil microbial community structure and respiration activity in an agricultural sandy loam. Effects of the chemicals were assessed through measurements of soil microbial respiration activity and soil bacterial and fungal community structure fingerprints, together with a degradation study of the chemicals, through a 70 d incubation period. Picoxystrobin caused a decrease in the respiration activity, while 4-n-nonylphenol caused an increase in respiration activity concurring with a rapid degradation of the substance. Community structure fingerprints were also affected, but these results could not be directly interpreted in terms of positive or negative effects, and were indicated to be transient. Treatment with the chemicals in mixture caused less evident changes and indicated antagonistic effects between the chemicals in soil. In conclusion, the results imply that the application of the fungicide picoxystrobin and nonylphenol from sewage sludge application to agricultural soil in environmentally relevant concentrations, as single chemicals or in mixture, will not cause irreversible effects on soil microbial respiration and community structure.

Uptake and translocation of organophosphates and other emerging contaminants in food and forage crops.

Emerging contaminants in wastewater and sewage sludge spread on agricultural soil can be transferred to the human food web directly by uptake into food crops or indirectly following uptake into forage crops. This study determined uptake and translocation of the organophosphates tris(1-chloro-2-propyl) phosphate (TCPP) (log Kow 2.59), triethyl-chloro-phosphate (TCEP) (log Kow 1.44), tributyl phosphate (TBP) (log Kow 4.0), the insect repellent N,N-diethyl toluamide (DEET) (log Kow 2.18) and the plasticiser N-butyl benzenesulfonamide (NBBS) (log Kow 2.31) in barley, wheat, oilseed rape, meadow fescue and four cultivars of carrot. All species were grown in pots of agricultural soil, freshly amended contaminants in the range of 0.6-1.0 mg/kg dry weight, in the greenhouse. The bioconcentration factors for root (RCF), leaf (LCF) and seed (SCF) were calculated as plant concentration in root, leaf or seed over measured initial soil concentration, both in dry weight. The chlorinated flame retardants (TCEP and TCPP) displayed the highest bioconcentration factors for leaf and seed but did not show the same pattern for all crop species tested. For TCEP, which has been phased out due to toxicity but is still found in sewage sludge and wastewater, LCF was 3.9 in meadow fescue and 42.3 in carrot. For TCPP, which has replaced TCEP in many products and also occurs in higher residual levels in sewage sludge and wastewater, LCF was high for meadow fescue and carrot (25.9 and 17.5, respectively). For the four cultivars of carrot tested, the RCF range for TCPP and TCEP was 10-20 and 1.7-4.6, respectively. TCPP was detected in all three types of seeds tested (SCF, 0.015-0.110). Despite that DEET and NBBS have log Kow in same range as TCPP and TCEP, generally lower bioconcentration factors were measured. Based on the high translocation of TCPP and TCEP to leaves, especially TCPP, into meadow fescue (a forage crop for livestock animals), ongoing risk assessments should be conducted to investigate the potential effects of these compounds in the food web.

Bioaccumulation of persistent organic pollutants (POPs) in fish species from Lake Koka, Ethiopia: The influence of lipid content and trophic position.

The concentrations and bioaccumulation of persistent organic pollutants (POPs) were determined in four fish species from Lake Koka, Ethiopia, representing 2-3 levels in the food chain of the lake. Dichlorodiphenyltrichloroethanes (DDTs), endosulfans, polychlorinated biphenyls (PCBs) and chlorpyrifos were identified, with DDTs as the most predominant pesticide, with concentration ranging from 0.05 to 72.53ngg(-1) wet weight (ww). All fish tissue samples collected from different species of the lake contained residues of DDTs. The maximum level of DDTs was found in the fattiest, African sharptooth catfish (Clarias gariepinus) sampled from the lake, with a mean concentration of 15.15ngg(-1)ww. The significant (P<0.05) relationship between concentrations of DDTs and δ(15)N indicates that DDTs biomagnified in the food web of the lake. The 4,4'-DDE to 4,4'-DDT ratio in Oreochromis niloticus (0.6) and Cyprinus carpio (0.5) were below 1, indicating ongoing use of DDTs in the study area and recent exposure of these fish species.

Application of QuEChERS method for extraction of selected persistent organic pollutants in fish tissue and analysis by gas chromatography mass spectrometry.

The QuEChERS method developed for 22 organochlorine pesticides (OCPs) and 7-polychlorinated biphenyls (PCBs) in fish tissue involves a simple and efficient freezing technique for removal of lipids. The equipment developed consists of disposable syringes and a freezing block constructed from simple materials found in most laboratories. The freezing block keeps the temperature in the extract at -20.5°C up to 10 min after being exposed to room temperature. After the freezing step 69% of the lipids in tilapia and 61% in salmon are removed. Further reduction of co-extractives up to 96% in tilapia and 87% in salmon can be made by treatment with CaCl(2) and primary secondary amino sorbent (PSA) which removes the fatty acids. Spiking experiments in tilapia at 5 and 50 ng/g and extracted with acetonitrile show recovery range from 70 to 115% for all compounds. In salmon the recoveries are in the range 43-118% for the OCPs and 26-65% for the PCBs. Analysis of a standard reference material shows acceptable results for most of the pesticides but low results for the PCBs. The estimated LOQs were in the range 1-5 ng/g for tilapia and 2-10 ng/g for salmon. The method has been applied to analyse fish samples from Lake Koka in Ethiopia. It was investigated if addition of a less polar water miscible solvent than acetonitrile could increase the recovery of OCPs and PCBs. The results show that a mixture of 75% acetonitrile and 25% tetrahydrofurane (ACN/THF 75/25) clearly enhances the recoveries for most OCPs (47-101%) and PCBs (42-79%) from salmon. The recovery of aldrin increases significantly from 55% to over 80%. The method using ACN/THF 75/25 is applicable to the extraction of OCPs and PCBs from fish tissue having a lipid content of up to about 11% (salmon) with recoveries ≥70% for most of the OCPs and ≥42% for the PCBs.

Independent evaluation of a commercial deconvolution reporting software for gas chromatography mass spectrometry analysis of pesticide residues in fruits and vegetables.

The gas chromatography mass spectrometry (GC-MS) deconvolution reporting software (DRS) from Agilent Technologies has been evaluated for its ability as a screening tool to detect a large number of pesticides in incurred and fortified samples extracted with acetone/dichloromethane/light petroleum (Mini-Luke method). The detection of pesticides is based on fixed retention times using retention time locking (RTL) and full scan mass spectral comparison with a partly customer built automated mass spectral deconvolution and identification system (AMDIS) database. The GC-MS was equipped with a programmable temperature vaporising (PTV) injector system which enables more sample to be injected. In a blind study of 52 real samples a total number of 158 incurred pesticides were found. In addition to the 85 pesticides found by manual interpretation of GC-NPD/ECD chromatograms, the DRS revealed 73 more pesticides (+46%). The DRS system also shows its potential to discover pesticides which are normally not searched for (EPN in long beans from Thailand). A spiking experiment was performed to blank matrices of apple, orange and lettuce with 177 different pesticides at concentration levels 0.02 and 0.1 mg/kg. The samples were analysed on GC-MS full scan and the AMDIS match factor was used as a mass spectral quality criterion. The threshold level of the AMDIS match factor was set at 20 to eliminate most of the false positives. AMDIS match factors from 20 up to 69 are regarded only as indication of a positive hit and must be followed by manual interpretation. Pesticides giving AMDIS match factors at > or = 70 are regarded as identified. To simplify and decrease the large amount of data generated at each concentration level, the AMDIS match factors > or = 20 was averaged (mean AMF) for each pesticide including the commodities and their replicates. Among 177 different pesticides spiked at 0.02 and 0.1 mg/kg level, the percentage of mean AMF values > or = 70 were 23% and 80%, respectively. For 531 individual detections of pesticides (177 pesticides x 3 replicates) giving AMDIS match factor 20 in apple, orange and lettuce, the detection rates at 0.02 mg/kg were 71%, 63% and 72%, respectively. For the 0.1 mg/kg level the detection rates were 89%, 85% and 89%, respectively. In real samples some manual interpretation must be performed in addition. However, screening by GC-MS/DRS is about 5-10 times faster compared to screening with GC-NPD/ECD because the time used for manual interpretation is much shorter and there is no need for re-injection on GC-MS for the identification of suspect peaks found on GC-NPD/ECD.

Bioassay-directed identification of toxic organic compounds in creosote-contaminated groundwater.

Despite the fact that creosote mainly consists of polycyclic aromatic hydrocarbons (PAHs), more polar compounds like phenolics, benzenes and N-, S-, O-heterocyclics dominate the groundwater downstream from creosote-contaminated sites. In this study, bioassay-directed fractionation, combined with fullscan GC-MS, identified organic toxicants in creosote-contaminated groundwater. An organic extract of creosote-contaminated groundwater was fractionated on a polar silica column using high performance liquid chromatography (HPLC), and the toxicity of the fractions was measured by the Microtox-bioassay. PAHs, which comprise up to 85% of pure creosote, accounted for only about 13% of total toxicity in the creosote-contaminated groundwater, while methylated benzenes, phenolics and N-heterocyclics accounted for ca. 80% of the measured toxicity. The fraction containing alkylated quinolines was the most toxic single fraction, accounting for 26% of the total measured toxicity. The results imply that focus on PAHs may underestimate risks associated with creosote-contaminated groundwater, and that environmental risk assessment should focus to a higher degree on substituted PAHs and phenolics because they are more toxic than the unsubstituted ones. Additionally, benzenes and N-heterocyclics (e.g., alkylated quinolines) should be assessed.