Department of Biochemistry, Microbiology and Biotechnology, Faculty of Biology, Yerevan State University, 1 Alex Manoogian Str., 0025 Yerevan, Armenia.
Scientific Research Institute of Biology, Faculty of Biology, Yerevan State University, 0025 Yerevan, Armenia.
FEMS Microbiol Lett. 2020 Jun 1;367(11). doi: 10.1093/femsle/fnaa088.
After brewing roasted coffee, spent coffee grounds (SCGs) are generated being one of the daily wastes emerging in dominant countries with high rate and big quantity. Escherichia coli BW25113 wild-type strain, mutants with defects in hydrogen (H2)-producing/oxidizing four hydrogenases (Hyd) (ΔhyaB ΔhybC, ΔhycE, ΔhyfG) and septuple mutant (ΔhyaB ΔhybC ΔhycA ΔfdoG ΔldhA ΔfrdC ΔaceE) were investigated by measuring change of external pH, bacterial growth and H2 production during the utilization of SCG hydrolysate. In wild type, H2 was produced with rate of 1.28 mL H2 (g sugar)-1 h-1 yielding 30.7 mL H2 (g sugar)-1 or 2.75 L (kg SCG)-1 during 24 h. In septuple mutant, H2 production yield was 72 mL H2 (g sugar)-1 with rate of 3 mL H2 (g sugar)-1 h-1. H2 generation was absent in hycE single mutant showing the main role of Hyd-3 in H2 production. During utilization of SCG wild type, specific growth rate was 0.72 ± 0.01 h-1 with biomass yield of 0.3 g L-1. Genetic modifications and control of external parameters during growth could lead to prolonged and enhanced microbiological H2 production by organic wastes, which will aid more efficiently global sustainable energy needs resulting in diversification of mobile and fixed energy sources.
酿造烤咖啡后，废咖啡渣（SCG）是一种在高产量和高消费国家每天产生的主要废物之一。野生型大肠杆菌 BW25113 菌株、氢产生/氧化四种氢化酶（Hyd）缺陷的突变体（ΔhyaB ΔhybC、ΔhycE、ΔhyfG）和七重突变体（ΔhyaB ΔhybC ΔhycA ΔfdoG ΔldhA ΔfrdC ΔaceE）被用来研究利用 SCG 水解物时外部 pH 值变化、细菌生长和 H2 生产的变化。在野生型中，H2 的产生速率为 1.28 mL H2（g 糖）-1 h-1，产生 30.7 mL H2（g 糖）-1 或 2.75 L（kg SCG）-1 ，24 h。在七重突变体中，H2 的产生速率为 3 mL H2（g 糖）-1 h-1，H2 的产生速率为 72 mL H2（g 糖）-1。HycE 单突变体中 H2 的产生不存在，表明 Hyd-3 在 H2 产生中的主要作用。在利用 SCG 野生型时，比生长速率为 0.72±0.01 h-1，生物量产率为 0.3 g L-1。在生长过程中对外部参数进行遗传修饰和控制，可以导致有机废物的微生物学 H2 产生延长和增强，这将有助于更有效地满足全球可持续能源需求，从而实现移动和固定能源的多样化。
