Viewpoint pubs.acs.org/JAFC
Trends in Food Enzymology Holger Zorn*,† and Qing X. Li§ †
Institute of Food Chemistry and Food Biotechnology, Justus Liebig University Giessen, Giessen, Germany Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, Honolulu, Hawaii 96822, United States standard and has replaced outdated linear approximations such as Lineweaver−Burk plots. To attract the interest of the broad, general audience of JAFC, manuscripts in the field of food enzymology must thus go beyond the sole cloning of cDNAs highly similar to wellknown catalysts and reporting of the enzyme’s kinetics, (marginally improved) pH and temperature optima, or the effects of various salts and chemicals on the enzyme’s characteristics. Instead of traveling well-worn paths, serious challenges that require strong joint endeavors of the scientific community should be addressed. Biocatalysts with novel catalytic properties are needed to make compounds available that are currently only derived from petrochemical processes. Replacing existing chemical processes for the synthesis of food additives, vitamins, and aroma compounds by ecologically friendlier alternatives will lower the processes’ carbon footprint and will contribute to the advancement of a future bioeconomy. In many cases, this will nzymes play important roles in food flavor, coloring, require multistep enzymatic cascade processes, and the texture, storage stability, nutrient absorption, and metabrespective activities (and the concentrations of potential cofactors) have to be carefully fine-tuned. The construction olism. Therefore, novel applications of enzymes in food of entire metabolic pathways in recombinant hosts, protein processing and food safety have become an alluring field of engineering, and (co)immobilization of the catalysts on food research. Highly efficient, selective, and stable enzymes are grade carriers are promising tools toward an efficient industrial required to meet the strong societal need for sustainable food production of the target compounds.1 However, many of the and feed production processes, on the one hand, and the biochemical pathways leading to functional food ingredients consumers’ demand for “natural” food, on the other hand. This and to flavor and taste active compounds in plants and is currently reflected by an increasing number of manuscripts microorganisms are still poorly understood and await their submitted to the Journal of Agricultural and Food Chemistry elucidation. In this respect, the combined and time-resolved (JAFC) reporting on food enzymes derived from various analysis of the proteome (or secretome), the transcriptome, sources including plants, higher animals, insects, bacteria, and and the metabolome of a producer organism may help to fungi. comprehensively understand fermentation processes, metabolic Whereas in the past it was a time-consuming and tedious task pathways, and interaction networks. Proper method calibration, to purify and biochemically characterize an enzyme and to validation, and standardization are essential for ensuring the amplify and clone its encoding cDNA, the availability of myriad validity of the data. Food and nutritional proteomics and genome sequences in data banks has changed the field of transcriptomics promote interesting hypotheses on links among enzyme research dramatically. DNA and cDNA sequences from enzymes, microbiomes, and the contribution of enzymes to archaea, bacteria, and eukaryotes, and even metagenomes may nutrition and health benefits. However, laboratory experiments now be easily searched (e.g., on the Joint Genome Institute are required to verify the hypotheses derived from -omics genome portal (http://genome.jgi.doe.gov/)), and sequences studies. coding for almost all types of biocatalysts can be identified via The targeted elimination of antinutritional factors, pesticides, homology comparisons. Sophisticated bioinformatic tools allow toxins, or veterinary antibiotics by specific enzymatic reactions for a prediction of the potential three-dimensional structure, may turn so far unsuitable or inaccessible renewable resources the presence of signal peptides, secondary structure elements, into raw materials for food and feed applications and, thus, contribute to a more efficient use of the available biomass. protein domains, and functional sites. As a consequence, the Similarly, allergens and substances causing food intolerances heterologous expression of a (c)DNA in a standard may be destroyed by appropriate enzymes. For example, the recombinant host such as Escherichia coli, Saccharomyces hydrolysis of proline-rich protein sequences by specific cerevisiae, or Pichia pastoris as well as the ensuing biochemical characterization of the corresponding enzyme often represent routine operations. Likewise, the calculation of enzyme kinetics Received: December 7, 2016 by appropriate nonlinear regression software has become §
E
© XXXX American Chemical Society
A
DOI: 10.1021/acs.jafc.6b05483 J. Agric. Food Chem. XXXX, XXX, XXX−XXX
Viewpoint
Journal of Agricultural and Food Chemistry endopeptidases may degrade gluten during the production process of cereal-based beverages or during the preparation of dough, and thus reduce the intolerance of patients suffering from celiac disease.2 Because recombinant production in bacterial and ascomycetous hosts of enzymes derived from higher eukaryotes can often have unforeseen problems (including missing or excessive posttranslational modifications, or proteolytic digestion), novel eukaryotic expression systems, such as those based on edible mushrooms (basidiomycetes) or insect cell lines, represent promising alternatives. Although the general molecular biological tools are already available, these hosts have been rarely employed for the expression of industrial food enzymes so far. Additionally, as the spreading of antibiotic resistance raises public safety concerns, the construction of production hosts devoid of unwanted antibiotic resistance genes is an important task. The removal of antibiotic resistance genes in recombinant hosts may be achieved by using systems such as Cre/lox, as reported recently for Bacillus subtilis.3 Given recent advances in the biochemical, genomic, and metabolic tools available, we feel that it is an ideal time for researchers in the area of food chemistry and nutrition to take up these highly exciting challenges and to ensure that society’s need for food products is being met. Therefore, the Journal of Agricultural and Food Chemistry strongly encourages the submission of manuscripts that address the progress in the field of food enzymology.
■
AUTHOR INFORMATION
Corresponding Author
*(H.Z.) Phone: +49 641 99-34900. Fax: +49 641 99-34909. Email:
[email protected]. ORCID
Holger Zorn: 0000-0002-8383-8196 Qing X. Li: 0000-0003-4589-2869 Notes
The authors declare no competing financial interest.
■
REFERENCES
(1) Yang, J.; Zhu, Y.; Men, Y.; Sun, S.; Zeng, Y.; Zhang, Y.; Sun, Y.; Ma, Y. Pathway construction in Corynebacterium glutamicum and strain engineering to produce rare sugars from glycerol. J. Agric. Food Chem. 2016, 64, 9497−9505. (2) Panda, R.; Fiedler, K. L.; Cho, C. Y.; Cheng, R.; Stutts, W. L.; Jackson, L. S.; Garber, E. A. E. Effects of a proline endopeptidase on the detection and quantitation of gluten by antibody-based methods during the fermentation of a model sorghum beer. J. Agric. Food Chem. 2015, 63, 10525−10535. (3) He, W.; Mu, W.; Jiang, B.; Yan, X.; Zhang, T. Food-grade expression of D-psicose 3-epimerase with tandem repeat genes in Bacillus subtilis. J. Agric. Food Chem. 2016, 64, 5701−5707.
B
DOI: 10.1021/acs.jafc.6b05483 J. Agric. Food Chem. XXXX, XXX, XXX−XXX
