气体沿面放电低温等离子体对扩展青霉孢子杀灭效果

Killing Effect of Low-Temperature Plasma Generated by Gas Phase Surface Discharge on Penicillium expansum Spores

目的:研究气体沿面放电低温等离子体对扩展青霉孢子的杀菌效果。方法:以扩展青霉标准菌株CICC 40658和扩展青霉分离菌株F-LPH10-06为目标菌株,探讨2株菌在马铃薯葡萄糖液体培养基中的生长和产毒特性;应用自制的气体沿面放电低温等离子体杀菌设备,探讨处理时间、电源电压及孢子不同初始浓度对杀菌效果的影响;并应用扫描电子显微镜对孢子形态变化进行观察。结果:扩展青霉CICC 40658和F-LPH10-06培养14 d后的菌体干质量分别为28.6 mg和128.7 mg,展青霉素含量分别为912.40μg/L和147.97 mg/L,F-LPH10-06产毒量几乎是CICC 40658产毒量的162倍。气体沿面放电低温等离子体21 min能全部杀死样品中CICC 40658孢子(初始浓度为3.4×10~6个/mL);处理30 min,能使样品中F-LPH10-06孢子(初始浓度为1.5×10~6个/mL)减少4.58 lg(个/mL)。在相同的处理时间下,随着电源电压升高和初始孢子浓度降低,杀菌效果逐渐提高。扫描电子显微镜结果表明,孢子表面形态经过放电处理后被改变,这可能与放电过程中产生的高能电子和活性氧有关。结论:气体沿面放电低温等离子体对扩展青霉孢子有一定杀灭作用,这为低温杀菌技术的发展和应用提供了理论依据。

Objective: This study was conducted to evaluate the fungicidal effect of low-temperature plasma generated by gas phase surface discharge on the spores of Penicillium expansum.Methods: Two strains(CICC 40658 and F-LPH10-06) of P.expansum were used to investigate their growth and patulin-producing characteristics in potato dextrose broth medium.Low-temperature plasma generated by gas phase surface discharge sterilizer was developed and used to study the effect of treatment time,power supply voltage and initial spore concentration on its fungicidal effect against P.expansum.Furthermore,the morphological changes of P.expansum spores were characterized using scanning electron microscopy(SEM).Results: The biomass(dry weight) of P.expansum CICC 40658 and F-LPH10-06 were 28.6 and 128.7 mg after 14 days of culture,respectively.The concentration of patulin produced by P.expansum F-LPH10-06 was 147.97 mg/L at the end of incubation,which was nearly 162 times higher than that produced by CICC 40658(912.40 μg/L).CICC 40658 at an initial concentration of 3.4 × 10~6 spores/m L could be completely killed after 21 min treatment by low-temperature plasma generated by gas phase surface discharge.For F-LPH10-06(1.5 × 10~6 spores/m L),a reduction of 4.58 lg(spores/m L) was observed after treatment for 30 min.In addition,the fungicidal effect was enhanced with the increase in discharge voltage or decrease in initial spore concentration after the same treatment time.SEM observation showed that the morphology of spores changed after treatment,which may be related to the charged particles with high energy and reactive oxygen species produced during high voltage discharge.Conclusion: Low-temperature plasma generated by gas phase surface discharge has strong fungicidal effect against P.expansum,which may provide an important theoretical basis for the development and application of low-temperature sterilization technology.