Cost reduction approaches for fermentable sugar production from sugarcane bagasse and its impact on techno-economics and the environment
Cost reduction approaches for fermentable sugar production from sugarcane bagasse and its impact on techno-economics and the environment
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DOI：
10.1007/s10570-021-03940-5
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发表时间：
2021-05-18
期刊：
影响因子：
5.7
通讯作者：
Agrawal, Deepti
中科院分区：
文献类型：
--
作者：
Baral, Pratibha;Munagala, Meghana;Agrawal, Deepti
在酶驱动的木质纤维素生物精炼厂中，预处理和水解模块是获得高浓度糖溶液的两个最主要成本因素。本研究旨在减少甘蔗渣生物加工过程中碱和Cellic CTec2的使用。随后评估了其对整个工艺经济性和环境的影响。在预处理过程中，15%（w/w）的固体负载量以及在121℃下使用2%（w/v）的氢氧化钠处理30分钟被证明是一种最佳策略。这使得甘蔗渣的木质素去除率>65%，预处理后的生物质中分别保留了≥90%的葡聚糖和65%的木聚糖成分。同时评估了两种方法以尽量减少这种商业纤维素酶混合物的需求。第一种策略是通过混合用自制的酶混合物部分替代它。第二种途径是在高于其最佳温度的情况下使用减少用量的纤维素酶混合物进行水解，这种方法取得了更有前景的结果。在52.5℃下，用剂量为15mg蛋白质/克葡聚糖的纤维素酶混合物对20%碱预处理的甘蔗渣进行水解，在48小时内葡聚糖和木聚糖的转化率分别达到84.13±1%和83.5±2.3%。滤液和洗涤液部分含有≥165和≥65g/L的糖单体，分别代表葡萄糖和木聚糖。然而，在这两个部分中，>75%的糖为葡萄糖。技术经济分析表明，采用优化的生物工艺，甘蔗渣制糖成本为1.32美元/千克。环境影响研究表明，就气候变化而言，该工艺产生了1.57kg二氧化碳当量的影响。
In an enzymatically driven lignocellulosic biorefinery, pretreatment and hydrolysis modules are the two most significant cost contributors for obtaining high gravity sugar solutions. The present study aimed to reduce the use of alkali and Cellic CTec2 during the bioprocessing of sugarcane bagasse (SCB). Later its impact on the overall process economics and the environment was evaluated. During pretreatment, solid loading of 15% (w/w) and use of 2% (w/v) sodium hydroxide at 121 degrees C for 30 min emerged as an optimum strategy. It resulted in > 65% delignification of SCB, retaining >= 90% and 65% of glucan and xylan fraction, respectively, in the pretreated biomass. Two approaches were evaluated in parallel to minimize the requirement of this commercial cellulase enzyme blend. The first strategy involved its partial replacement with an in-house enzyme cocktail by blending. The second route was performing hydrolysis with reduced loadings of cellulase enzyme blend above its optimum temperature, which gave more promising results. Hydrolysis of 20% alkali pretreated SCB with cellulase enzyme blend dosed at 15 mg protein g(-1) glucan led to 84.13 +/- 1 and 83.5 +/- 2.3% glucan and xylan conversion yields respectively in 48 h at 52.5 degrees C. The filtrate and wash fraction contained >= 165 and >= 65 g L-1 sugar monomers representing glucose and xylose. However, in both the fractions > 75%, sugar accounted for glucose. The techno-economic analysis revealed that the sugar production cost from SCB was 1.32 US$/kg, with the optimized bioprocess. Environmental impact study showed that the process contributed to 1.57 kg CO2 eq in terms of climate change.