Degradation of Zearalenone by Microorganisms and Enzymes: A Review

Degradation of Zearalenone by Microorganisms and Enzymes: A Review

Jiregna Gari^*

Department of Agriculture, College of Agriculture and Veterinary Sciences, Ambo University, Ambo, Ethiopia

*Corresponding Author:: Jiregna Gari
Department of Agriculture,
College of Agriculture and Veterinary Sciences,
Ambo University,
Ambo,
Ethiopia,
Tel: 0924460446;
E-mail: jiregnagari@gmail.com

Received date: September 12, 2022, Manuscript No. IPMMO-22-14523; Editor assigned date: September 15, 2022, PreQC No. IPMMO-22-14523 (PQ); Reviewed date: September 30, 2022, QC No. IPMMO-22-14523; Revised date: Januaryr 18, 2023, Manuscript No. IPMMO-22-14523 (R); Published date: January 25, 2023, DOI: 10.36648/2471-8521.9.1.049

Citation: Gari J (2023) Degradation of Zearalenone by Microorganisms and Enzymes: A Review. Med Mycol Open Access Vol:9 No:1

Visit for more related articles at Medical Mycology: Open Access

Abstract

Mycotoxins are toxic metabolites produced by fungi that may cause serious health problems in humans and animals. Zearalenone (ZEN) is an estrogenic mycotoxin produced by Fusarium species that leads to huge economic losses in the food industry and livestock husbandry. Contamination of food and feed with zearalenone has reproductive problems, carcinogenicity, immunotoxicity and other cytotoxic effects. At present, microorganisms and enzymes derived from microbial strains have been widely used for the degradation of zearalenone in food and feed. Researchers have developed biodegradation of ZEN by the use of microbial and their enzyme derivatives, which offers harmless products and is environmentally friendly. Development of recombinant enzymes improves enzymatic detoxification of zearalenone to a non-toxic product without damaging the nutritional content. This review summarizes biodegradation of zearalenone using microorganisms and enzyme derivatives to nontoxic products.

Keywords

Degradation; Enzyme; Microorganisms; Mycotoxins; Zearalenone (ZEN)

Abbreviations:

GSF: Simulated Gastric Fluid; HPLC: High Performance Liquid Chromatography; TOF-MS: Time of Flight Mass Spectrometry; NMR: Nuclear Magnetic Resonance; ZEN: Zearalenone; ZENC: Zearalenone lactonase gene from Neurospora Crassa

Introduction

Mycotoxins are naturally occurring toxic secondary metabolites of some microscopic filamentous fungi [1]. Mycotoxins produced mainly by some fungal species belonging to Alternaria, Aspergillus, Fusarium and Penicillium genera pose health threats to humans and animals [2]. Mycotoxins contamination of foods and feeds is a current global issue and causes huge economic losses to animal husbandry [3].

More than 400 different types of mycotoxins have been identified so far, with different levels of toxicity [4]. Among all mycotoxins, aflatoxins B1, zearalenone, ochratoxin A, patulin and trichothecenes have received particular attention due to their severe health outcomes on both humans and animals, which can range from acute to severe and chronic intoxications in both humans and animals [5,6].

Bouajila, et al. reported that zearalenone contaminate feeds like corn, wheat, barley, sorghum, rice and other grains and have a variety of toxic effects on humans and animals [7,8]. Zearalenone (ZEN) is a potent non-steroidal oestrogen mycotoxin which is biosynthesized via the polyketide pathway and could bind to estrogen receptors, which subsequently activate estrogen response elements in animals [9,10].

Zearalenone (ZEN) consumption causes hypoestrogenism in animals and interferes in the expression of estrogen and organ function [11]. It could reduce the nutritional value of feed, damage the growth and health of livestock and poultry and cause huge economic losses to livestock production. However, some animals, like chickens, show strong resistance to the toxicity of ZEN. ZEN can also cause abortion, infertility, stillbirth and other reproductive effects on animals [12].

In humans, ZEN has a chronic toxicity effect and stimulates the growth of mammary gland cells that might be involved in breast cancer [13]. There is a report that shows ZEN has immunotoxin, hepatotoxic, hematotoxic and reproductive toxic effects like reducing fertility, vaginal prolapse and causing vulvar swelling.

Literature Review

The degradation of zearalenone toxicity is commonly done by the use of physical, chemical and biological approaches. Zearalenone is heat stable and shows great resistance to conventional degradation methods [14,15]. However, physical and chemical degradation destroys nutritional structure, decreases palatability of the feed and causes pollution to the environment [16]. Biological degradation has great specificity and degrades zearalenone completely without producing harmless products [17].

Recently, numerous studies have focused on degradation through biological approaches by using microorganisms including bacteria, yeast and fungi and microorganisms’ enzymes to remove zearalenone from food sources [18]. Development of genetic engineering technology in the advancement of recombinant proteins improves enzymatic degradation of zearalenone. This review aims to discuss the biological degradation of ZEN through microorganisms and enzymes developed in recent years.

Degradation of zearalenone by microorganisms

Microbial degradation occurs when microorganisms (bacterial and yeast) secrete their metabolites or enzymes during their growth and development process. Microorganisms can directly adsorb targeted toxins or reduce toxins of our interest to impede the production of mycotoxins [19].

Many studies have reported on the biodegradation of ZEN using microorganisms. They show high specificity and ecofriendliness in decreasing the possibility of ZEN toxicity from food and feed [20]. A variety of non-pathogenic microbes like probiotics, Bacillus, Saccharomyces and Lactobacillus species have a high capability to detoxify feeds contaminated with zearalenone because they follow standards like safe to be used and possess detoxifying ability without forming bad odor or taste in the feeds [21,22].

Many studies reveal detoxification of zearalenone using probiotics, including by yeast, Bacillus and lactic acid bacteria, as they are involved in adsorption of ZEN and preventing its absorption by animals [23].

Various bacteria, yeasts and fungi can convert ZEN to alpha and beta zearalenol [24]. Among Bacillus strains, B. licheniformis, B. subtilis, B. natto and B. cerues were those found to have the highest detoxification effect on zearalenon in food and feed. Bacillus pumlius ANSB01G is also reported to degrade ZEN in the feed of animals. According to Xu, et al. B. amyloliquefaciens ZDS-1 has ZEN degrading ability in screened colonies [25-29].

Probiotics is a great choice for biodegradation of ZEN in the food industry because it shows health benefits for humans and animals. Most Lactic Acid Bacteria (LABs) are considered safe probiotics in the food industry. It is reported that Lactobacillus strains have a potential role in degrading ZEN from fermented food products [26]. Lact. paracasei and Lc. lacti have the ability to remove ZEN in aqueous food solutions. There is a report that shows zearalenone can be degraded from PBS buffer solution by Lact. Acidophilus CIP 76.13 T by a bioremediation range of 57% [30,31].

Discussion

There is a report that shows B. licheniformis CK1 has good probiotic properties and can degrade ZEN by more than 90% after 36 hours of incubation in the contaminated corn meal medium by ZEN [32]. Other strains of bacteria called Saccharomyces cerevisiae also have high ZEN degradation abilities. There is a report that shows S. cerevisiae isolate from grape can degrade ZEN [33-37].

Saccharomyces cerevisiae isolated from silage has biodegradation properties and can degrade up to 90% of ZEN in two days [38]. According to Harkai, et, al. the bacteria Streptomyces rimosus (K145, K189) can degrade ZEN in liquid media. Wang, et al. also investigated whether a Lysinibacillus strain isolated from chicken large intestine digesta is capable of degrading zearalenone (Table 1) [39,40].

Food source or media used	Strain	ZEN concentration	Degradation range
Liquid LB medium	Streptomyces rimosus (K145, K189)	1 µg mL^-1	100%
Feed	Bacillus licheniformis CK1	1.20 ± 0.11, 0.47 ± 0.22 mg/kg	Can degrade ZEN
Liquid chromatography-tandem mass spectrometry and Thin layer chromatography	Candida parapsilosis	20 μg/mL	Decreased by 97%
Potassium phosphate buffer	Lact. plantarum 3QB361	2 μg/mL	82%
Aqueous solution	Lact. plantarum BCC 47723	0.2 μg/mL	0.5%-23%
Culture medium/liquid food /solid-state fermentation	Bacillus subtilis Bacillus natto	20 ug/mL; 1 mg/kg; 20 μg/Ml	100% and 87% 65, 73%/75%, 70%
Nutrient broth	Bacillus subtilis, Candida utilis, Aspergillus oryzae	1 µg/mL	92.27% A. oryzae. combined form can degrade 95.15%
Malting wheat grains with bacterial suspension	P. acidilactici	19.5-873.7 µg/L	38.00%
LB medium and Simulated Gastric Fluid (GSF)	Bacillus cereus BC7	10 mg/L	100% and 89.31%
Corn meal medium	B. licheniformis CK1	5 μg/mL	73%
Culture medium	Bacillus pumilus ES 21	17.9 mg/ml	95.70%
MRS broth	Lactobacillus rhamnosus	200 µg/mL	Showed the highest adsorption (68.2%)
MRS broth	Lactobacillus plantarum ZJ316	5 mg/L	highest ZEA degradation ability
The LB medium	Acinetobacter calcoaceticus	5 μg/mL	85.77%
HPLC-TOF-MS and NMR	B. subtilis Y816	40 mg/L	Transform of ZEN within 7 hour
Cell suspensions on MRS agar	Lb. fermentum 2I3, Lb. reuteri L26, Lb. plantarum L81, Lb. reuteri, Lb. plantarum CCM 1904,	0.01 ppm	(57.9-100)%
Cell suspensions on MRS agar	Bacillus subtilis CCM 2794	0.01 ppm	11.70%

Table 1: Recent research that shows microorganisms used for the degradation of zearalenone (ZEN).

Degradation of zearalenone by enzymes

Recent advancements in genetic engineering technology have attracted researchers' attention towards recombinant enzymes to degrade mycotoxins in food and feed with high efficiency. The attainment and cloning of recombinant enzyme genes leads to the safe expression of genes in microbes, which has become a novel progress in molecular modification for ZEN degradation [41-44].

Enzymatic degradation has wide advantages over microbial degradation because it can perform biodegradation with high efficiency, lower cost, reproducibility and homogenous performance [45-47].

A bacterial strain of E. coli, S. cerevisiae and Pichia pastoris has been reported to remove ZEN from culture medium [48-54]. Gao, et al. identify and describe the activity of the ZEN degrading enzyme from Exophiala spinifera, ZHD_LD. Recently, microbial strains that are able to degrade ZEN have been isolated and subsequently genes like ZHD101, ZLHY-6 and ZENjjm, as well as ZHD518 have been cloned [55,56]. ZHD101 is one of the recombinant enzymes derived from Clonostachys rosea that degrades ZEN.

Wang, et al. reported that the lactonohydrolase Zhd518 enzyme in E. coli has high biodegrading ability against ZEN in food and feed industries. There is a study that shows RmZHD, a ZEN hydrolyzing enzyme from Rhinocladiella mackenziei, has the ability to degrade ZEN [57].

Recombinant Prx (peroxiredoxin), a cloned gene from Acinetobacter sp. SM04 expressed in E. coli, has the ability to degrade ZEN in the presence of hydrogen peroxide [58]. It has been reported that laccase enzymes that are found on bacterial and yeast cells have the ability to degrade mycotoxins [59-62]. Song, et al. show the laccase gene obtained from the fungus P. pulmonarius has an enzymatic property to degrade zearalenone when it was expressed in the Pichia pastoris X33 yeast strain by producing recombinant protein.

Studies have shown that laccase enzymes are considered to be an effective zealenone toxicity a ntidote. Furthermore, Pleurotus eryngii laccase enzyme can degrade aflatoxin B1, ochratoxin A, zearalenon and other mycotoxins.

A gene ZENC, zearalenone lactonase gene from Neurospora crassa, is expressed in P. pastoris. It had a maximal enzyme activity when fermented using high density fermatation at pH 8 and a temperature of 45°C. Furthermore, ZENC was also found to be effective in ZEN containing feed materials with a high degradation rate [63].

Garcia, et al. also reported that the peroxidase enzyme has the ability to degrade zearalenone concentrations. According to the study, fusion of multifunctional recombinant enzymes ZHDCP with genes of ZEN hydrolases and carboxypeptidases has the ability to detoxify zearalenone in 2 hours at pH and temperature of 35°C (Table 2) [64].

Enzymes name	Source	Expression system	Degrading properties
Peroxiredoxin	Acinetobacter sp. SM04	S. cerevisiae	Optimal activity at pH 9.0, 80°C and H₂O₂ concentration of 20 mmol/L thermal stable, alkali resistance
Lactone hydrolase ZHD	Gliocladium roseum	P. pastoris	Enzyme activity in flask fermentation was 22.5 U/mL and specific activity of 4976.5 U/mg. Maximum enzyme activity of the supernatant was 150.1 U/ml in 5 L fermenter
Cb ZHD	C. rosea	Cladophialophora bantiana	Optimal enzyme activity at temperature 35°C and pH 8
Lactonohydrolase	Clonostachys rosea	Lactobacillus reuteri pg4	Not affect cell growth, acid and bile salt tolerance
Lactonohydrolase Zhd518	Clonostachys rosea	E. coli	Activity of 207.0 U/mg with optimal temperature 40°C and pH 8.
Lactonase	Neurospora crassa	P. pastoris	Optimal activity at pH 8.0 and 45°C, stable at pH 6.0-8.0 for 1 h at 37°C, Maximal enzyme activity at 290.6 U/mL in 30-L fermenter
Lactonehydrolase ZENC	Neurospora crassa	P. pastoris	99.75% of ZEN (20 μg/ml) was degraded at pH 8.0, 45°C for 15 min
Fusion ZHDCP enzyme	C. rosea B.amyloliquefaciens ASAG	E. coli	100% degradation rate at pH 7 and 30°C
ZLHY-6	Pichia pastoris	P. pastoris GSZ	low nutrient loss safe removal of ZEN
lac2	Pleurotus pulmonarius	P. pastoris X33	Lac2-ABTS and Lac2-AS degrade ZEN at optimum pH 3.5 and temperature 55°C of recombinant Lac2
Lactonohydrolase	Trichoderma aggressivum	E. coli BL21	With superior pH stability, the surface exhibit ZHD-P retained 80% activity
ZPF1	C. rosea fused with Phanerochaete chysosporium	Kluyveromyces lactis GG799	ZEN degraded up to 46.21% ± 3.17%
DyP	Streptomyces thermocarboxydus 41291	E. coli BL21	ZEN was degraded slightly by StDyP
Ase	Acinetobacter Sp	E. coli BL21	Degraded 88.4% of ZEN (20 µg/mL)

Table 2: Enzymatic degradation of zearalenone (ZEN).

Conclusion

The severe impact of zealarenone on animals and humans' health, present in contaminated food and feed, has received global attention. Many approaches have been established for the removal of ZEN. Biodegradation is considered the safest approach because it degrades toxins without residual toxic substances. Recent research shows the development of recombinant microorganisms and recombinant enzymes to detoxify ZEN in foods and feeds. However, the health impacts of recombinant enzymes are not clearly described. Currently, biodegradation of zealarenone is laboratory based. The commercial scale of biodegradation needs further studies. Further interdisciplinary studies concerning gene cloning, genetic modification of microorganisms and the development of recombinant enzymes are promising approaches for safe zealarenone degradation.