Abdelmalek Fady, Steinbüchel Alexander, Rofeal Marian
International Center for Research on Innovative Biobased Materials (ICRI-BioM)-International Research Agenda, Lodz University of Technology, Zeromskiego 116, 90-924 Lodz, Poland.
Department of Botany and Microbiology, Faculty of Science, Alexandria University, Moharam Bek, Alexandria 21521, Egypt.
Polymers (Basel). 2022 Jul 10;14(14):2810. doi: 10.3390/polym14142810.
Bioplastics are contemplated as remarkable substitutes for conventional plastics to accommodate green technological advancements. However, their industrial production has not been fully implemented owing to the cost of carbon resources. From another perspective, valorizing different paper mill wastes has become a prominent research topic. These materials may serve as an affording sustainable feedstock for bioplastic production. Adjustment of cardboard waste hydrolysate as suitable fermentation media for production of bacterial polyhydroxyalkanoates (PHAs) has been investigated. Cardboard samples were defibered and dried before enzymatic hydrolysis. The enzymatic degradation of commercial cellulase was monitored over 15 days. Interestingly, 18.2 ± 0.2 g/L glucose yield was obtained from 50 g cardboard samples using a 1.5% (/) enzyme concentration. The samples exhibited maximum weight loss values of 69-73%. Meanwhile, five soil samples were collected from local sites in Lodz, Poland. A total of 31 bacterial isolates were screened and cultured on Nile blue plates. Analysis of the 16S rRNA gene sequence of the most potent producer revealed 100% similarity to . Cardboard hydrolysates whole medium, modified MSM with cardboard hydrolysate and nitrogen depleted MSM with cardboard hydrolysate were utilized for PHA production, followed by PHA productivity and cell dry weight (CDW) estimation compared to glucose as a standard carbon source. An impressive PHA accumulation of 56% CDW was attained when the waste hydrolysate was used as a carbon source. FTIR and NMR analysis of the isolated PHA indicated that functional groups of the polymer were related to PHB (polyhydroxybutyrate). Thermal analysis demonstrates that PHB and PHB-CB (PHB produced from cardboard hydrolysate) have degradation temperatures of 380 and 369 °C, respectively, which reflect the high thermal stability and heat resistance compared to the same properties for a standard polymer. This is the first demonstration of full saccharification of corrugated cardboard paper waste for high-level production of PHA. In addition, the attained PHB productivity is one of the highest levels achieved from a real lignocellulosic waste.
生物塑料被视为传统塑料的显著替代品，以适应绿色技术进步。然而，由于碳资源成本，其工业化生产尚未完全实现。从另一个角度来看，将不同的造纸厂废料进行增值利用已成为一个突出的研究课题。这些材料可作为生物塑料生产的可持续原料。已对将纸板废料水解产物调整为适合生产细菌聚羟基脂肪酸酯（PHA）的发酵培养基进行了研究。在酶解之前，将纸板样品解离并干燥。对商业纤维素酶的酶解过程进行了15天的监测。有趣的是，使用1.5%（/）的酶浓度，从50克纸板样品中获得了18.2±0.2克/升的葡萄糖产量。样品的最大失重值为69 - 73%。同时，从波兰罗兹当地采集了五个土壤样本。共筛选出31株细菌分离株，并在尼罗蓝平板上进行培养。对最有效的生产者的16S rRNA基因序列分析显示与……有100%的相似性。将纸板水解产物全培养基、含纸板水解产物的改良MSM培养基和含纸板水解产物的氮耗尽MSM培养基用于PHA生产，然后与作为标准碳源的葡萄糖相比，估算PHA生产力和细胞干重（CDW）。当使用废料水解产物作为碳源时，实现了令人印象深刻的56% CDW的PHA积累。对分离出的PHA进行的FTIR和NMR分析表明，该聚合物的官能团与聚羟基丁酸酯（PHB）有关。热分析表明，PHB和PHB - CB（由纸板水解产物生产的PHB）的降解温度分别为380和369℃，与标准聚合物的相同性能相比，这反映了其高热稳定性和耐热性。这是首次证明瓦楞纸板废料完全糖化以用于高水平生产PHA。此外，所获得的PHB生产力是从真正的木质纤维素废料中实现的最高水平之一。
