Structure and spectroscopy of methionyl-methionine for aquaculture

Stewart F Parker,Kenneth Shankland,Sascha Braune,Hans-Joachim Hasselbach,Elena A Kabova,Nicholas P Funnell,Christoph Kobler,Peter W Albers,Thomas Häußner

doi:10.1038/s41598-020-80385-z

Stewart F Parker, Kenneth Shankland + Show 7 more

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https://doi.org/10.1038/s41598-020-80385-z

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Abstract

The amino acid l-methionine is an essential amino acid and is commonly used as a feed supplement in terrestrial animals. It is less suitable for marine organisms because it is readily excreted. It is also highly water soluble and this results in loss of the feed and eutrophication of the water. To address these problems, the dipeptide dl-methionyl-dl-methionine (trade name: AQUAVI Met-Met) has been developed as a dedicated methionine source for aquaculture. The commercial product is a mixture of a racemic crystal form of d-methionyl-d-methionine/l-methionyl-l-methionine and a racemic crystal form of d-methionyl-l-methionine/l-methionyl-d-methionine. In this work, we have computationally, structurally, spectroscopically and by electron microscopy characterised these materials. The microscopy and spectroscopy demonstrate that there is no interaction between the dd–ll and dl–ld racemates on any length scale from the macroscopic to the nanoscale.

Highlights

The amino acid l-methionine is an essential amino acid and is commonly used as a feed supplement in terrestrial animals
In contrast to its use as a feed supplement in terrestrial animals, methionine is less suitable for marine organisms
A full understanding of the physicochemical properties of various crystalline forms of a commercially important material such as Met-Met is critical to understanding its solid-state behaviour, both during processing and in use, and crystal structure determination is a key element of this understanding

Summary

Introduction

The amino acid l-methionine is an essential amino acid and is commonly used as a feed supplement in terrestrial animals. It is highly water soluble and this results in loss of the feed and eutrophication of the water To address these problems, the dipeptide dl-methionyl-dl-methionine (trade name: AQUAVI Met-Met) has been developed as a dedicated methionine source for aquaculture. Methionine is highly water soluble (50–55 g L−1) and this results in loss of the feed and eutrophication of the water To address these problems, the dipeptide dl-methionyl-dl-methionine (trade name: AQUAVI Met-Met, CAS-No.: 52715-93-2) has been developed[7,8] as a dedicated methionine source for aquaculture e.g. for bottom feeders such as shrimp, prawn and other crustaceans[9,10,11]. We have structurally characterised the commercially important d-methionyld-methionine/l-methionyl-l-methionine and d-methionyl-l-methionine/l-methionyl-d-methionine, and report complete assignments of their solid-state spectra. We have used a combination of inelastic

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