Paraszkiewicz Katarzyna, Frycie Aleksandra, Słaba Mirosława, Długoński Jerzy
Department of Industrial Microbiology and Biotechnology, University of Łódź, Banacha 12/16, PL-90237 Lodz, Poland.
Biometals. 2007 Oct;20(5):797-805. doi: 10.1007/s10534-006-9043-x. Epub 2006 Nov 22.
The influence of cadmium, zinc and lead on fungal emulsifier synthesis and on the growth of filamentous fungus Curvularia lunata has been studied. Tolerance to heavy metals established for C. lunata was additionally compared with the sensitivity exhibited by strains of Curvularia tuberculata and Paecilomyces marquandii-fungi which do not secrete compounds of emulsifying activity. Although C. lunata, as the only one out of all studied fungi, exhibited the lowest tolerance to heavy metals when grown on a solid medium (in conditions preventing emulsifier synthesis), it manifested the highest tolerance in liquid culture - in conditions allowing exopolymer production. Cadmium, zinc and lead presented in liquid medium up to a concentration of 15 mM had no negative effect on C. lunata growth and stimulated emulsifier synthesis. In the presence of 15 mM of heavy metals, both the emulsifier and 24-h-old growing mycelium exhibited maximum sorption capacities, which were determined as 18.2 +/- 2.67, 156.1 +/- 10.32 mg g(-1) for Cd2+, 22.2 +/- 3.40, 95.2 +/- 14.21 mg g(-1) for Zn2+ and 51.1 +/- 1.85, 230.0 +/- 28.47 mg g(-1) for Pb2+ respectively. The results obtained by us in this work indicate that the emulsifier acts as a protective compound increasing the ability of C. lunata to survive in heavy metal polluted environment. Enhancement of exopolymer synthesis in the presence of Cd2+, Zn2+ and Pb2+ may also suggest, at least to some extent, a metal-specific nature of emulsifier production in C. lunata. Due to accumulation capability and tolerance to heavy metals, C. lunata mycelium surrounded by the emulsifier could be applied for toxic metal removal.
研究了镉、锌和铅对真菌乳化剂合成以及丝状真菌新月弯孢霉生长的影响。此外，还将新月弯孢霉对重金属的耐受性与不分泌乳化活性化合物的结核弯孢霉和马克兰德拟青霉菌株所表现出的敏感性进行了比较。尽管新月弯孢霉是所有研究真菌中唯一在固体培养基上生长时（在防止乳化剂合成的条件下）对重金属耐受性最低的，但在液体培养中（在允许产生胞外聚合物的条件下）它表现出最高的耐受性。液体培养基中浓度高达15 mM的镉、锌和铅对新月弯孢霉的生长没有负面影响，反而刺激了乳化剂的合成。在存在15 mM重金属的情况下，乳化剂和24小时龄的生长菌丝体都表现出最大吸附容量，Cd2+分别为18.2±2.67、156.1±10.32 mg g(-1)，Zn2+为22.2±3.40、95.2±14.21 mg g(-1)，Pb2+为51.1±1.85、230.0±28.47 mg g(-1)。我们在这项工作中获得的结果表明，乳化剂作为一种保护化合物，提高了新月弯孢霉在重金属污染环境中生存的能力。在Cd2+、Zn2+和Pb2+存在下胞外聚合物合成的增强也至少在一定程度上表明了新月弯孢霉中乳化剂产生的金属特异性性质。由于具有积累能力和对重金属的耐受性，被乳化剂包围的新月弯孢霉菌丝体可用于去除有毒金属。
