Jaffur Nausheen, Jeetah Pratima, Kumar Gopalakrishnan
Department of Chemical and Environmental Engineering, Faculty of Engineering, University of Mauritius, Réduit, 80837 Mauritius.
Institute of Chemistry, Bioscience and Environmental Engineering, Faculty of Science and Technology, University of Stavanger, Stavanger, Norway.
3 Biotech. 2021 Nov;11(11):483. doi: 10.1007/s13205-021-03009-x. Epub 2021 Oct 30.
Currently, major focus in the biopolymer field is being drawn on the exploitation of plant-based resources grounded on holistic sustainability trends to produce novel, affordable, biocompatible and environmentally safe polyhydroxyalkanoate biopolymers. The global PHA market, estimated at USD 62 Million in 2020, is predicted to grow by 11.2 and 14.2% between 2020-2024 and 2020-2025 correspondingly based on market research reports. The market is primarily driven by the growing demand for PHA products by the food packaging, biomedical, pharmaceutical, biofuel and agricultural sectors. One of the key limitations in the growth of the PHA market is the significantly higher production costs associated with pure carbon raw materials as compared to traditional polymers. Nonetheless, considerations such as consumer awareness on the toxicity of petroleum-based plastics and strict government regulations towards the prohibition of the use and trade of synthetic plastics are expected to boost the market growth rate. This study throws light on the production of polyhydroxybutyrate from lignocellulosic biomass using environmentally benign techniques via enzyme and microbial activities to assess its feasibility as a green substitute to conventional plastics. The novelty of the present study is to highlight the recent advances, pretreatment techniques to reduce the recalcitrance of lignocellulosic biomass such as dilute and concentrated acidic pretreatment, alkaline pretreatment, steam explosion, ammonia fibre explosion (AFEX), ball milling, biological pretreatment as well as novel emerging pretreatment techniques notably, high-pressure homogenizer, electron beam, high hydrostatic pressure, co-solvent enhanced lignocellulosic fractionation (CELF) pulsed-electric field, low temperature steep delignification (LTSD), microwave and ultrasound technologies. Additionally, inhibitory compounds and detoxification routes, fermentation downstream processes, life cycle and environmental impacts of recovered natural biopolymers, review green procurement policies in various countries, PHA strategies in line with the United Nations Sustainable Development Goals (SDGs) along with the fate of the spent polyhydroxybutyrate are outlined.
目前，基于整体可持续发展趋势，生物聚合物领域的主要焦点在于利用植物基资源来生产新型、价格合理、生物相容且环境安全的聚羟基脂肪酸酯生物聚合物。根据市场研究报告，2020年全球聚羟基脂肪酸酯市场估计为6200万美元，预计在2020 - 2024年和2020 - 2025年间将分别以11.2%和14.2%的速度增长。该市场的主要驱动力是食品包装、生物医学、制药、生物燃料和农业等行业对聚羟基脂肪酸酯产品不断增长的需求。聚羟基脂肪酸酯市场增长的一个关键限制因素是，与传统聚合物相比，纯碳原料的生产成本显著更高。尽管如此，消费者对石油基塑料毒性的认识以及政府对禁止合成塑料使用和贸易的严格监管等因素，预计将推动市场增长率。本研究通过酶和微生物活动，利用环境友好型技术，阐明了从木质纤维素生物质生产聚羟基丁酸酯的过程，以评估其作为传统塑料绿色替代品的可行性。本研究的新颖之处在于突出了近期的进展、降低木质纤维素生物质难降解性的预处理技术，如稀酸和浓酸预处理、碱性预处理、蒸汽爆破、氨纤维爆破（AFEX）、球磨、生物预处理以及新兴的预处理技术，特别是高压均质机、电子束、高静水压、共溶剂强化木质纤维素分级（CELF）、脉冲电场、低温深度脱木质素（LTSD）、微波和超声技术。此外，还概述了抑制性化合物和解毒途径、发酵下游工艺、回收天然生物聚合物的生命周期和环境影响、各国的绿色采购政策、符合联合国可持续发展目标（SDGs）的聚羟基脂肪酸酯策略以及废弃聚羟基丁酸酯的去向。
