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A German language conference abstract. It's title in English: Upcycling of side-streams of the food industry with edible fungi: Fermentation of pasta residuals to an alternative protein source with garlic flavour.

Whole-cell cultures of the basidiomycetous white-rot fungus Dichomitus albidofuscus exhibit varying catalytic activity towards aromatic compounds depending on the growth stage. This study reveals the catalytic behavior of mature whole-cell cultures that effectively catalyze a C−C bond cleavage oxidizing toluene, benzaldehyde and acetophenone to phenol. The reaction products were analyzed by GC-MS and NMR techniques. To exclude the de novo formation of phenol by the fungus, its origin has been proven by bioconversion of benzaldehyde-d5. The key step involves an aerobic Baeyer-Villiger type rearrangement where the incorporation of oxygen into the product was confirmed based on isotope labelling experiments with 18O2. Intermediate esters were not found in reaction mixture presumably due to the detected esterase activity in the mycelium as well as in supernatant of the whole-cell cultures. As a result, the sequence of biocatalytic reactions catalyzed by D. albidofuscus for the degradation of toluene via C−C bond cleavage has been disclosed.

Submerged cultures of the basidiomycota Cystostereum murrayi emit an intensive coconut-like, sweetish, and buttery smell. For identification of the key aroma compounds, an aroma dilution analysis using dynamic headspace was performed by adjusting the split ratio of the GC inlet system. Flavor dilution (FD) factors varied from 22 up to >218, whereby the largest class of compounds represented terpenoids, including two rare stereoisomers of 3,6-dimethyl-2,3,3a,4,5,7a-hexahydrobenzofuran (dill ether, ee > 99.9). By means of nuclear magnetic resonance spectroscopy, the substances with the highest FD factors (29, 212, and 218) were identified as diastereomers of 3,6-dimethyl-3a,4,5,6,7,7a-hexayhydro-3H-1-benzofuran-2-one (dihydromenthofurolactone) and as its corresponding C3-unsaturated lactone. The latter two compounds have not been described for Cystostereum murrayi or for any other basidiomycota previously. Supplementation studies using 2-13C-d-glucose indicated that these lactones as well as the two stereoisomers of dill ether and other terpenoids were formed de novo by the fungus.

Hepatic steatosis is a very common response to liver injury and often attributed to metabolic disorders. Prior studies have demonstrated the efficacy of a biotechnologically produced oyster mushroom (Pleurotus sajor-caju, PSC) in alleviating hepatic steatosis in obese Zucker rats. This study aims to elucidate molecular events underlying the anti-steatotic effects of PSC. Tandem mass tag (TMT) peptide labeling coupled with LC-MS/MS/MS was used to quantify and compare proteins in the livers of lean Zucker rats fed a control diet (LC), obese Zucker rats fed the same control diet (OC) and obese Zucker rats fed the control diet supplemented with 5% PSC (OPSC) for 4 weeks. Using this technique 3128 proteins could be quantified, out of which 108 were differentially abundant between the OPSC and OC group. Functional enrichment analysis of the up-regulated proteins showed that these proteins were mainly involved in metabolic processes, while the down-regulated proteins were involved in inflammatory processes. Results from proteomic analysis were successfully validated for two up-regulated (carbonic anhydrase 3, regucalcin) and two down-regulated (cadherin-17, ceruloplasmin) proteins by means of immunoblotting.

Lipid extracts of the fungus Flammulina velutipes were found to contain various scarce fatty acids including dodec-11-enoic acid and di- and tri-unsaturated C16 isomers. A biotechnological approach using a heterologously expressed carboxylic acid reductase was developed to transform the fatty acids into the respective aldehydes, yielding inter alia dodec-11-enal. Supplementation studies gave insights into the fungal biosynthesis of this rarely occurring acid and suggested a terminal desaturation of lauric acid being responsible for its formation. A systematic structure-odor relationship assessment of terminally unsaturated aldehydes (C7-C13) revealed odor thresholds in the range of 0.24-22 mg/L in aqueous solution and 0.039-29 ng/L in air. In both cases, non-8-enal was identified as the most potent compound. All aldehydes exhibited green odor qualities. Short-chained substances were additionally associated with grassy, melon-, and cucumber-like notes, while longer-chained homologs smelled soapy and coriander leaf-like with partly herbaceous nuances. Dodec-11-enal turned out to be of highly pleasant scent without off-notes.

To meet consumer expectations, white wines must be clear and stable against haze formation. Temperature variations during transport and storage may induce protein aggregation, mainly caused by thaumatin like-proteins (TLPs) and chitinases (CHIs), which thus need to be fined before bottling of the wine. Currently, bentonite clay is employed to inhibit or minimize haze formation in wines. Alternatively, peptidases have emerged as an option for the removal of these thermolabile proteins, although their efficacy under winemaking conditions has not yet been fully demonstrated. The simultaneous understanding of the chemistry behind the cleavage of haze proteins and the haze formation may orchestrate alternative methods of technological and economic importance in winemaking. Therefore, we provide an overview of wine fining by peptidases, and new perspectives are developed to reopen discussions on the aforementioned challenges.

Brown-rot fungi are particularly suitable for the sustainable and cost-efficient biotechnological production of natural flavors. In this study, Wolfiporia cocos was employed for the fermentation of European black currant pomace supplemented with aspartate in surface cultures to produce a flavor reminiscent of wild strawberries. Aroma dilution analysis (ADA) by means of dynamic headspace extraction was developed as a suitable technique for solid samples. The character impact compounds were quantified by stable isotope dilution analysis and standard addition and validated by recombination experiments. (R)-Linalool (1879 mg kg-1, ADA 211), methyl anthranilate (2206 mg kg-1, 210), 2-aminobenzaldehyde (771 mg kg-1, 25), and geraniol (138 mg kg-1, 25) were identified as key aroma compounds. Recombination experiments demonstrated that the combination of the four analyzed compounds was responsible for the odor impression reminiscent of wild strawberries.

The reductive activity of various basidiomycetous fungi towards carbonyl compounds was screened on an analytical level. Some strains displayed high reductive activities toward aromatic carbonyls and aliphatic ketones. Utilizing growing whole-cell cultures of Dichomitus albidofuscus, the reactions were up-scaled to a preparative level in an aqueous system. The reactions showed excellent selectivities and gave the respective alcohols in high yields. Carboxylic acids were also reduced to aldehydes and alcohols under the same conditions. In particular, benzoic, vanillic, ferulic, and p-coumaric acid were reduced to benzyl alcohol, vanillin, dihydroconiferyl alcohol and 1-hydroxy-3-(4-hydroxyphenyl)propan, respectively.

Culture supernatants of Basfia succiniciproducens derived from the industrial production of succinic acid exhibit an intense nutty, root vegetable-like, buttery and sourish smell. By means of headspace-gas chromatography-mass spectrometry-olfactometry (HS-GC-MS-O), 14 odour-active compounds were perceived and identified using two GC-columns of different polarity and comparison of retention indices and mass spectra to those of authentic reference compounds. Several alkylated pyrazines, including 2,3,5-trimethylpyrazine, 5-ethyl-2,3-dimethylpyrazine, 2,3,5,6-tetramethylpyrazine, 2,3,5-trimethyl-6-ethylpyrazine, 2,3,5-trimethyl-6-propylpyrazine and 2,3,5-trimethyl-6-butylpyrazine were found to contribute to the aroma of the culture supernatant. Quantitation of the pyrazines was performed by means of dynamic headspace-GC-MS after standard addition, and 2,3,5,6-tetramethylpyrazine (9.10 mg/L) was the most abundant compound. Waste streams of the biotechnological production of commodity chemicals may thus represent a sustainable resource for the isolation of aroma compounds.

The 12th Wartburg Symposium on Flavor Chemistry & Biology was held at the hotel ""Auf der Wartburg"" in Eisenach, Germany, from May 21 to 24, 2019. It offered a unique venue for global exchange on cutting-edge research progress in chemistry and biology of odor and taste. The focus areas were (1) chemosensory perception and signal processing, (2) flavor systems: molecular decoding, interactions, and perception, (3) new computational approaches in flavor chemistry, (4) functional flavor genomics and biotechnology, (5) food-borne bioactives: molecular decoding, interactions, and perception, and (6) next-generation technologies in flavor molecule and precursor discovery. Selected from more than 250 applicants, 160 distinguished scientists and early career researches from industry and academia from 24 countries and 4 continents participated in this inspiring and multidisciplinary event. This special issue comprises a selection of 20 papers from oral presentations and poster contributions and is prefaced by this introduction paper.

In recent years, black soldier fly, Hermetia illucens (L.), larvae have attracted increasing attention because of their high capacity for bioconversion of diverse organic material into high-quality protein and lipids. Although previous studies have focused on optimization of breeding conditions, such as the acceptance of substrates, and temperatures and moisture contents, little is known about light-dependent adult development. Artificial light sources are important to commercial H. illucens breeding, especially at latitudes with short days in autumn and winter months. We examined how 3,000, 4,000, and 6,500 K color temperatures affect aspects of oviposition. Mating occurred under all of the broad spectrum light-emitting diode panels, resulting in fertilized egg clusters. Oviposition lasted up to 15 d, while the shortest oviposition period, in the 3,000 K light treatment, was 2 d. Total oviposition performance and oviposition period were not affected by the light treatments. Oviposition peaked 1-7 d after eggs were first deposited. The time until oviposition peaked was positively correlated with increasing color temperature.

Fructo-oligosaccharides (FOS) are low-calorie sweeteners that can be synthesized by the transfructosylation of sucrose using enzymes known as fructosyltransferases. However, enzymatic conversion is inhibited by the accumulation of glucose as a byproduct, which limits the conversion rate and yield. We therefore developed a semi-continuous production process in an enzyme membrane bioreactor (EMBR) system followed by fermentation with the probiotic bacterium Bacillus coagulans. Filtration experiments were conducted in total recycle mode to evaluate membrane fouling using the resistance-in-series model. We found that fouling was predominantly caused by the accumulation of proteins at the membrane surface, which accounted for 29.6-95.5% of the total filtration resistance depending on the conditions. Using these data, we were able to achieve a stable filtration flux that fulfilled the requirements of the EMBR system by regulating the filtration parameters. The average concentration of total FOS in the products of EMBR reached 270 g·L−1, which was 4.6% higher than the batch process. Subsequently, the crude FOS preparation was treated by fed-batch fermentation with B. coagulans. The monosaccharides in the reaction mix (glucose and fructose) were completely removed, increasing the concentration of FOS to 195.9 g·L−1 and the purity to 96.6%.

Scope The hypothesis is tested that insect meal, which has a low methionine content, reduces the hepatic phosphatidylcholine (PC):phosphatidylethanolamine (PE) ratio, which is a critical determinant of hepatic lipid synthesis, by decreasing availability of the methionine metabolite S‐adenosylmethionine (SAM). Methods and results Obese rats (n = 24) are randomly divided into two groups (Obese Casein and Obese Insect) of 12 rats each. In addition, lean rats (n = 12) are used as control group (LC). Groups LC and OC receive a control diet with casein as protein source, whereas in the OI group, casein is replaced isonitrogenously by insect meal, which is found to be less digestible (-12% units). Plasma and liver concentrations of lipids and hepatic expression of lipid synthesizing genes are reduced in the OI group compared to the OC group. Plasma and liver concentration of PC and the PC:PE ratio are decreased in the OI group compared to the OC group, while hepatic concentration of SAM and the hepatic SAM:S‐adenosylhomocysteine (SAH) ratio is lower in the OI group than in the OC group. Conclusion The decrease of the hepatic PC:PE ratio is probably a key mechanism explaining the pronounced antisteatotic and hypolipidemic action of insect meal in obese rats.

The white-rot fungus Pleurotus sapidus (PSA) biosynthesizes the bicyclic monoterpenoids 3,6-dimethyl-2,3,3a,4,5,7a-hexahydrobenzofuran (dill ether) (1) and 3,6-dimethyl-3a,4,5,7a-tetrahydro-1-benzofuran-2(3H)-one (wine lactone) (2). Submerged cultures grown in different media were analyzed by gas chromatography-mass spectrometry. The stereochemistry of the formed isomers was elucidated by comparing their retention indices to those of reference compounds by enantioselective multidimensional gas chromatography. The basidiomycete produced the rare (3R,3aR,7aS) and (3S,3aR,7aS) stereoisomers of dill ether and wine lactone. Kinetic analyses of the volatilome and bioprocess parameters revealed that the biosynthesis of the bicyclic monoterpenoids correlated with the availability of the primary carbon source glucose. Spiking the media with 13 C-labeled glucose demonstrated that the compounds were produced de novo. Supplementation studies i.a. with isotopically labeled substrate s further identified limonene and p-menth-1-en-9-ol as intermediate compounds in the fungal pathways. PSA was able to biotransform all enantiomeric forms of the latter compounds to the respective isomers of dill ether and wine lactone.

Although internationally recognized as the ""highest priority critically important antimicrobials,"" fluoroquinolones are extensively used in both human and veterinary medicine. Poor metabolism and recalcitrance of fluoroquinolones have led to their worldwide presence in municipal wastewaters as well as in manure and, consequently, in several environmental compartments. Being one of the most widely used fluoroquinolones in human medicine and, aside from that, the main metabolite of the veterinary drug enrofloxacin, ciprofloxacin is the most frequently detected fluoroquinolone in effluents of European wastewater treatment plants. Due to serious global concerns about the increasing emergence of bacterial (multi)resistances toward the highly efficient fluoroquinolones, special attention has been paid to their environmental degradation by various microorganisms. This review summarizes research on microbial transformation and degradation of fluoroquinolones with special emphasis on ciprofloxacin, presents an overview of the main ciprofloxacin biotransformation products, and takes a closer look at their biological relevance. Furthermore, own data, experiences, and publications gathered from our recent research in the field are acknowledged.

Purpose Novel protein sources are urgently needed to meet the increasing protein demand of a continuously growing world population. This study is focused on the production of protein rich mushroom mycelia on industrial side streams. Methods Submerged propagation of mushrooms was carried out in shake flasks which contained agro-industrial side streams as the sole carbon source. The biomass obtained was analyzed for its crude protein, ash and fat content as well as for its fatty acid and amino acid profiles. Vitamin D2 production from ergosterol in the biomass was induced by UV-B irradiation and determined by HPLC-DAD. The share of fungal mycelium in the total biomass was determined by extraction and quantitation of ergosterol. Additionally, water and oil binding capacity (WBC and OBC) were evaluated. Results A screening of basidiomycetes grown on agro-industrial side streams indicated a fast growth of Pleurotus sapidus on apple pomace. After 4 days of cultivation, the biomass obtained from this mushroom-substrate combination contained 21% true protein in dry matter. In addition to proteins, the amounts of lipids (4%), ash (2%) and carbohydrates (74%) were quantitated. The dominating fatty and amino acids of Pleurotus sapidus grown on apple pomace were linoleic acid and glutamic acid/glutamine, respectively. Concentrations of up to 115 µg (g dry matter)−1 vitamin D2 were formed from ergosterol by UV-B irradiation. Ergosterol was used as a biomarker to monitor the amount of fungal content. Conclusion The nutritional value of agro-industrial side streams such as apple pomace can be upcycled by biotransformation with basidiomycetes.

The ""Bioflavour 2018-Biotechnology of Flavors, Fragrances, and Functional Ingredients"" conference was held from September 18th to 21st, 2018 at the DECHEMA house in Frankfurt, Germany. The conference attracted more than 190 participants from over 25 countries, with about 40% share from industry. Particular sessions of Bioflavour 2018 focused on ""flavor perception and biotechnology"", ""microbial cell factories"", ""novel pathways, enzymes, and biocatalysts"", ""technological and regulatory aspects of flavor and fragrance biotechnology"", ""advanced analytics and novel compounds"", ""plant biosynthesis and plant enzymes"", ""modern biotechnology in the world of wine"", ""receptors, flavors, and bioactives"", and ""bioprocess development and downstream processing"". At Bioflavour 2018, both cutting-edge science from renowned academic research groups and current innovation from this modern biotechnology industry were presented and discussed. This special issue highlights a selection of 12 manuscripts from oral presentations and poster contributions.