Vostrejs Pavel, Adamcová Dana, Vaverková Magdalena Daria, Enev Vojtech, Kalina Michal, Machovsky Michal, Šourková Markéta, Marova Ivana, Kovalcik Adriana
Department of Food Chemistry and Biotechnology, Faculty of Chemistry, Brno University of Technology Purkynova 118 612 00 Brno Czech Republic
Department of Applied and Landscape Ecology, Faculty of AgriSciences, Mendel University in Brno Zemědělská 1 613 00 Brno Czech Republic.
RSC Adv. 2020 Aug 7;10(49):29202-29213. doi: 10.1039/d0ra04074f. eCollection 2020 Aug 5.
Biodegradable packaging materials represent one possible solution for how to reduce the negative environmental impact of plastics. The main idea of this work was to investigate the possibility of utilizing grape seed lignin for the modification of polyhydroxyalkanoates with the use of its antioxidant capacity in packaging films. For this purpose, polymeric films based on the blend of high crystalline poly(3-hydroxybutyrate) (PHB) and amorphous polyhydroxyalkanoate (PHA) were prepared. PHB/PHA films displayed Young modulus of 240 MPa, tensile strength at a maximum of 6.6 MPa and elongation at break of 95.2%. The physical properties of PHB/PHA films were modified by the addition of 1-10 wt% of grape seeds lignin (GS-L). GS-L lignin showed a high antioxidant capacity: 238 milligrams of Trolox equivalents were equal to one gram of grape seeds lignin. The incorporation of grape seeds lignin into PHB/PHA films positively influenced their gas barrier properties, antioxidant activity and biodegradability. The values of oxygen and carbon dioxide transition rate of PHB/PHA with 1 wt% of GS-L were 7.3 and 36.3 cm m 24 h 0.1 MPa, respectively. The inhibition percentage of the ABTS radical determined in PHB/PHA/GS-L was in the range of 29.2% to 100% depending on the lignin concentration. The biodegradability test carried out under controlled composting environment for 90 days showed that the PHB/PHA film with 50 w/w% of amorphous PHA reached the degradability degree of 68.8% being about 26.6% higher decomposition than in the case of neat high crystalline PHB film. The degradability degree of PHA films in compost within the tested period reflected the modification of the semi-crystalline character and varied with the incorporated lignin. From the toxicological point of view, the composts obtained after biodegradation of PHA films proved the non-toxicity of PHB/PHA/GS-L materials and its degradation products showed a positive effect on white mustard ( L.) seeds germination.
可生物降解包装材料是减少塑料对环境负面影响的一种可能解决方案。这项工作的主要思路是研究利用葡萄籽木质素通过其在包装薄膜中的抗氧化能力来改性聚羟基脂肪酸酯的可能性。为此，制备了基于高结晶聚（3-羟基丁酸酯）（PHB）和无定形聚羟基脂肪酸酯（PHA）共混物的聚合物薄膜。PHB/PHA薄膜的杨氏模量为240MPa，最大拉伸强度为6.6MPa，断裂伸长率为95.2%。通过添加1-10wt%的葡萄籽木质素（GS-L）对PHB/PHA薄膜的物理性能进行了改性。GS-L木质素显示出高抗氧化能力：238毫克的Trolox当量等于1克葡萄籽木质素。将葡萄籽木质素掺入PHB/PHA薄膜中对其气体阻隔性能、抗氧化活性和生物降解性产生了积极影响。含1wt%GS-L的PHB/PHA的氧气和二氧化碳透过率分别为7.3和36.3cm·m⁻²·24h⁻¹·0.1MPa。在PHB/PHA/GS-L中测定的ABTS自由基抑制率在29.2%至100%范围内，具体取决于木质素浓度。在受控堆肥环境下进行90天的生物降解试验表明，含50w/w%无定形PHA的PHB/PHA薄膜的降解程度达到68.8%，比纯高结晶PHB薄膜的分解率高约26.6%。在测试期间，PHA薄膜在堆肥中的降解程度反映了半结晶特性的改变，并随掺入的木质素而变化。从毒理学角度来看，PHA薄膜生物降解后获得的堆肥证明了PHB/PHA/GS-L材料无毒，其降解产物对白芥种子萌发有积极影响。
