INRS-ETE, Université Du Québec, 490, Rue de La Couronne, Québec, G1K 9A9, Canada.
INRS-ETE, Université Du Québec, 490, Rue de La Couronne, Québec, G1K 9A9, Canada; Department of Civil Engineering, Lassonde School of Engineering, York University, North York, Toronto, ON, M3J 1P3, Canada.
Chemosphere. 2021 Oct;281:130858. doi: 10.1016/j.chemosphere.2021.130858. Epub 2021 May 13.
The current work investigates the impact of using immobilized Rhizopus oryzae NRRL 1526 for bioproduction of fumaric acid using agro-industrial residues as feedstock. This use of agro-industrial residues, a renewable feedstock, for the production of bio-based platform chemical makes the process cost-competitive as well as greener by preventing the release of assimilable organic carbon to the environment, thereby reducing the generation of greenhouse gases. Immobilization of R. oryzae has been proposed previously to alleviate operational difficulties confronted during free mycelial fungal fermentation. To this effect, three synthetic refuse materials namely polystyrene foam, polyester sponge and polyurethane foam were investigated for their suitability towards fumaric acid bioproduction. Polystyrene foam was identified as the most suitable support material for immobilization as well as fumaric acid production. In addition to the considerable reduction in the lag-phase (from 48 to 24 h) the reduction in the size of the support material from cubes of 1 cm to beads of 0.1-0.3 cm led to a 42% improvement in fumaric acid production (27 g/L against 19 g/L). Growing the polystyrene foam bead immobilized R. oryzae on apple pomace ultrafiltration sludge as sole feedstock yielded a final fumaric acid titer of 7.9 g/L whereas free mycelial fermentation yielded 6.3 g/L. Moreover, upon operating the fermentation with intermittent feeding, a three-fold increase (1.7 g/L to 5.1 g/L) in fumaric acid production was obtained upon supplementation of the apple pomace sludge media with molasses, an agro-industrial residue, as feed.
本研究考察了利用固定化米根霉 NRRL 1526 以农业工业废料为原料生产富马酸的效果。利用农业工业废料作为可再生原料生产生物基平台化学品，不仅可以防止可同化有机碳释放到环境中，从而减少温室气体的产生，而且还可以降低生产成本，使工艺更加环保。先前已经提出了固定化米根霉的方法，以缓解游离丝状真菌发酵过程中遇到的操作困难。为此，研究了三种合成废料材料，即聚苯乙烯泡沫、聚酯海绵和聚氨酯泡沫，以评估它们在富马酸生物生产中的适用性。结果表明，聚苯乙烯泡沫是最适合固定化和富马酸生产的支撑材料。除了明显缩短了延滞期（从 48 小时缩短至 24 小时）之外，将支撑材料的尺寸从 1 厘米的立方体减小到 0.1-0.3 厘米的珠粒还使富马酸产量提高了 42%（从 27 克/升提高到 19 克/升）。将聚苯乙烯泡沫珠粒固定化米根霉生长在苹果渣超滤污泥上作为唯一的饲料，最终富马酸的浓度达到 7.9 克/升，而游离丝状真菌发酵的产量为 6.3 克/升。此外，在间歇进料的发酵操作中，通过在苹果渣污泥培养基中添加农业工业废料糖蜜作为饲料，富马酸的产量增加了三倍（从 1.7 克/升增加到 5.1 克/升）。
