Mitigation of acrylamide by l-asparaginase from Bacillus subtilis KDPS1 and analysis of degradation products by HPLC and HPTLC.

Gaurav Sanghvi,Tejas Oza,Devendra Vaishnav,Gaurav Dave,Prashant Kunjadia,Navin Sheth,Kapil Bhimani

doi:10.1186/s40064-016-2159-8

Gaurav Sanghvi, Tejas Oza + Show 5 more

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https://doi.org/10.1186/s40064-016-2159-8

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Abstract

The use of bacterial l-asparaginase (LA) is one of the alternative approaches for acrylamide reduction in food stuffs as it catalyzes the conversion of l-asparagine to l-aspartic acid and ammonia. In present investigation, purification of extracellular LA from isolate of Bacillus subtilis sp. strain KDPS-1 was carried out by solid state fermentation process. The effects of solid substrates, initial moisture content, moistening agents, temperature, and incubation time on LA production was studied, and the highest asparaginase activity (47 IU/ml) was achieved in the medium having orange peel as substrate. The enzyme was purified to homogeneity by diethylaminoethyl (DEAE) cellulose ion exchange chromatography; with 84.89 % yield and 12.11 fold purity. LA showed stimulant activity against β-mercaptoethanol and was greatly inhibited by Zn2+ and Hg2+ metal ions. Reduction of acrylamide in fried potatoes was detected by high performance liquid chromatography, which showed clear degradation of acrylamide by height and area (%) in the chromatograms of standard sample to that of the test sample. Hydrolysates analysis by high performance thin layer chromatography confirmed the test sample to be LA.

Highlights

LA (l-asparagine amido hydrolase, E.C. 3.5.1.1.) is a tetrameric enzyme that catalyzes the hydrolysis of nonessential amino-acid l-asparagine to l-aspartic acid and ammonia (Ruyssen and Lauwers 1978)
Acrylamide formation in foods is influenced by several factors that includes processing temperature, time, content and species of reducing sugars, pH, moisture content
Screening of bacterial strains for LA activity The present study focuses on the isolation of bacterial species for production of LA enzyme with its application in degradation of acrylamide in potato chips

Summary

Introduction

LA (l-asparagine amido hydrolase, E.C. 3.5.1.1.) is a tetrameric enzyme that catalyzes the hydrolysis of nonessential amino-acid l-asparagine to l-aspartic acid and ammonia (Ruyssen and Lauwers 1978). Free asparagine was found to be the main source of acrylamide which was converted in presence of reducing carbohydrates at temperature above 120 °C (Mottram et al 2002). It has been confirmed that a wide range of industrial, catering or homemade foods contains high levels of acrylamide. Acrylamide was found in certain staple foods like fried potatoes and coffee as well as in baked products like potato chips, biscuits, french fries, bread, and a range of. Acrylamide that forms during the heating of certain foods at high temperatures and low moisture conditions was considered as a potential cause of cancer (Gokmen et al 2006). Acrylamide formation in foods is influenced by several factors that includes processing temperature, time, content and species of reducing sugars, pH, moisture content

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