Das Arijit, Bhattacharya Sourav, Palaniswamy Muthusamy, Angayarkanni Jayaraman
Department of Microbiology, Karpagam University, Coimbatore, 641021, Tamil Nadu, India.
Department of Microbiology, Centre for Advanced Studies in Biosciences, Jain University, Bangalore, 560019, Karnataka, India.
3 Biotech. 2015 Jun;5(3):279-284. doi: 10.1007/s13205-014-0228-7. Epub 2014 Jun 11.
Aflatoxin B1 (AFB1) produced by Aspergillus flavus is known to have carcinogenic and teratogenic effects on animal health. Accidental feeding of AFB1-contaminated rice straw may be detrimental to dairy cattle. White-rot basidiomycetous fungus Pleurotus ostreatus can grow on different agronomic wastes by synthesizing different ligninolytic enzymes. These extracellular enzymes are capable of degrading many environmentally hazardous compounds including AFB1. The present study examines the ability of different strains of P. ostreatus to degrade AFB1 in contaminated rice straw. Different strains of A. flavus were inoculated on rice straw for AFB1 production. The moldy straw was then subjected to co-cultivation by different strains of P. ostreatus. The extent of AFB1 degradation was determined by high performance liquid chromatography. Results indicated the presence of AFB1 in the moldy straw samples at levels of 27.95 ± 0.23 and 21.26 ± 0.55 µg/g of dry substrate for A. flavus MTCC 2798 and A. flavus GHBF09, respectively. Co-cultivation of P. ostreatus strains on AFB1-contaminated rice straw revealed their ability to rapidly colonize the substrate by profuse hyphal ramification. Highest degradation of AFB1 (89.41 %) was recorded in the straw containing co-cultures of A. flavus MTCC 2798 and P. ostreatus GHBBF10. Natural isolate P. ostreatus GHBBF10 demonstrated higher AFB1-degradation potential than P.ostreatus MTCC 142. This basidiomycete strain can be further exploited to effectively degrade moderate concentrations of AFB1 in contaminated moldy rice straw.
黄曲霉产生的黄曲霉毒素B1（AFB1）对动物健康具有致癌和致畸作用。意外喂食受AFB1污染的稻草可能对奶牛有害。白腐担子菌平菇能够通过合成不同的木质素分解酶在不同的农业废弃物上生长。这些胞外酶能够降解包括AFB1在内的许多对环境有害的化合物。本研究考察了不同平菇菌株对受污染稻草中AFB1的降解能力。将不同的黄曲霉菌株接种在稻草上以产生AFB1。然后将发霉的稻草与不同的平菇菌株进行共培养。通过高效液相色谱法测定AFB1的降解程度。结果表明，对于黄曲霉MTCC 2798和黄曲霉GHBF09，发霉稻草样品中AFB1的含量分别为27.95±0.23和21.26±0.55μg/g干基质。平菇菌株在受AFB1污染的稻草上共培养显示出它们能够通过大量的菌丝分支迅速在基质上定殖。在含有黄曲霉MTCC 2798和平菇GHBBF10共培养物的稻草中，AFB1的降解率最高（89.41%）。天然分离的平菇GHBBF10表现出比平菇MTCC 142更高的AFB1降解潜力。这种担子菌菌株可进一步用于有效降解受污染发霉稻草中中等浓度的AFB1。
