预处理方式对微紫青霉菌吸附Cu2+的影响及其吸附机理

Effects of pre-treatment on Cu2+ absorption of Penicillium janthinellum strain GXCR

摘要:

为有效提高青霉菌(Penicillium)对含Cu2+的水溶液中的Cu2+的吸附能力并了解其吸附机制, 研究了8种不同预处理方式对微紫青霉菌(Penicillium janthinellum)菌株GXCR的Cu2+吸附的影响。结果表明, 匀浆化、匀浆+碱化(NaOH) (简称匀浆碱化)、高温(80oC)、匀浆+盐化(NaCl)、匀浆+洗涤剂和匀浆+极化(二甲基亚砜)可显著提高菌体的吸附率, 但是匀浆化+酸化处理会导致菌体的Cu2+吸附能力显著下降。与早期其他研究相比, 本研究发现匀浆化碱化(NaOH)相结合的方式能够显著提高菌体的吸附能力。其中匀浆碱化(NaOH, 0.5 mol/L)处理后菌体的Cu2+的吸附率增加了47.95%; 匀浆碱化菌体吸附符合典型的Langmuir方程, 表明该菌对吸附Cu2+的吸附可能是以表面吸附为主。吸附-解吸循环4次后, 碱化菌体的Cu2+的吸附率仍可达到70.82%。红外光谱分析表明碱化处理主要影响菌体表面分子的-OH、C=O和COOH基团中的C=O, 其中与Cu2+结合的主要基团是-OH。GXCR的对Cu2+的吸附可能是主要基于Cu2+与菌体-OH基团结合的化学吸附为主。

Abstract:

In order to effectively increase capacity of Cu2+ absorption by Penicillium from Cu2+-containing aqueous solution and to study the mechanisms of absorption, effects of eight pre-treatment methods on Cu2+ absorption of Penicillium janthinellum strain GXCR were compared. The results showed that the efficiency of Cu2+ absorption obviously increased through pre-treatment by homogenization, homogenization-basification (NaOH), oven dry (80oC), homogenization-salinification (NaCl), homogenization- detergent and homogenization-polarization (C2H6SO), but significantly decreased after acidification pretreatment with H2SO4. In comparison with the previous reports, the pretreatment in a homogenization-NaOH way could more efficiently enhance the Cu2+ absorption capacity of this fungus. Homogenization-basification (0.5 mol/L NaOH) increased Cu2+ biosorption by 47.95%. The Cu2+ absorption of the mycelia treated by homogenization-basification followed Langmuir isotherm equation, suggesting a surface absorption process. After four cycles of absorption-desorption, mycelia pretreated by homogenization-alkalization still had 70.82% of Cu2+ biosorption efficiency. Infrared reflectance analysis indicated that alkalization treatment made marked effects on molecular groups of C–H, C=O, and C=O in COOH on the mycelial surfaces, and -OH was a key Cu2+-binding group. It is therefore suggested that the Cu2+ absorption by the GXCR is likely to be a chemical absorption process through Cu2+ binding with -OH group on the mycelia.