Discovery of Novel Bacterial Chalcone Isomerases by a Sequence-Structure-Function-Evolution Strategy for Enzymatic Synthesis of (S)-Flavanones.

Chalcone isomerase (CHI) is a key enzyme in the biosynthesis of flavonoids in plants. The first bacterial CHI (CHI ) was identified from Eubacterium ramulus, but its distribution, evolutionary source, substrate scope, and stereoselectivity are still unclear. Here, we describe the identification of 66 novel bacterial CHIs from Genbank using a novel Sequence-Structure-Function-Evolution (SSFE) strategy.

Biotechnological Production and Sensory Evaluation of ω1-Unsaturated Aldehydes.

Lipid extracts of the fungus were found to contain various scarce fatty acids including dodec-11-enoic acid and di- and tri-unsaturated C isomers. A biotechnological approach using a heterologously expressed carboxylic acid reductase was developed to transform the fatty acids into the respective aldehydes, yielding 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.

Biotechnological Production of Odor-Active Methyl-Branched Aldehydes by a Novel α-Dioxygenase from .

As a result of their pleasant odor qualities and low odor thresholds, iso- and anteiso-fatty aldehydes represent promising candidates for applications in flavoring preparations. A novel cyanobacterial α-dioxygenase from was heterologously expressed in and applied for the biotechnological production of C-C branched-chain fatty aldehydes. The enzyme has a sequence identity of less than 40% to well-investigated α-dioxygenase from rice.

Biotechnological Production of Methyl-Branched Aldehydes.

A number of methyl-branched aldehydes impart interesting flavor impressions, and especially 12-methyltridecanal is a highly sought after flavoring compound for savory foods. Its smell is reminiscent of cooked meat and tallow. For the biotechnological production of 12-methyltridecanal, the literature was screened for fungi forming iso-fatty acids.

Enzymatic conversion of flavonoids using bacterial chalcone isomerase and enoate reductase.

Flavonoids are a large group of plant secondary metabolites with a variety of biological properties and are therefore of interest to many scientists, as they can lead to industrially interesting intermediates. The anaerobic gut bacterium Eubacterium ramulus can catabolize flavonoids, but until now, the pathway has not been experimentally confirmed. In the present work, a chalcone isomerase (CHI) and an enoate reductase (ERED) could be identified through whole genome sequencing and gene motif search.

Acetylcholinesterase inhibitors from the toadstool Cortinarius infractus.

Inhibition of acetylcholinesterase (AChE) and therefore prevention of acetylcholine degradation is one of the most accepted therapy opportunities for Alzheimer s disease (AD), today. Due to lack of selectivity of AChE inhibitor drugs on the market, AD-patients suffer from side effects like nausea or vomiting. In the present study the isolation of two alkaloids, infractopicrin (1) and 10-hydroxy-infractopicrin (2), from Cortinarius infractus Berk.

Alkaloids from the mushroom Pseudobaeospora pyrifera, pyriferines A-C.

Three novel alkaloids (1-3), named pyriferines A-C, were isolated from fruiting bodies of Pseudobaeospora pyrifera. They possess an unusual eight-membered N/O-acetal ring, derived from L-glutamic acid, that is connected to an enolized 1,3-diketo moiety. The structures were determined by spectroscopic methods, and the absolute configuration of the glutamic acid moiety was established using GC-MS after Mosher-type derivatization.