After brewing roasted coffee spent coffee grounds (SCG) are generated being one of the daily wastes emerging in dominant countries with high rate and big quantity. E. 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 SCGs 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, 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.

中文翻译：

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烘焙咖啡废料作为大肠杆菌生长和产生氢的底物。

酿造烤咖啡后，产生的废咖啡渣（SCG）成为占主导地位的国家中出现率高，数量大的日常废物之一。对大肠杆菌BW25113野生型菌株，产生/氧化四种氢化酶（Hyd）（ΔhyaBΔhybC，ΔhycE，ΔhyfG）和七种突变体的氢（H ₂）有缺陷的突变体（通过ΔfrdCΔEhCΔfrdC考察了ΔhhBΔhybCΔhycAΔfdoGΔldhA）SCG水解产物利用过程中外部pH值，细菌生长和H ₂产生的影响。在野生型，H ₂，用1.28毫升H的速率生产₂（克糖^{） -1} ħ ^-1得到30.7毫升水₂（g糖）^-1或2.75 L（kg SCG）^-1在24小时内。在九个突变体中，H _2的产量为72 mL H ₂（g糖）^-1，产率为3 mL H ₂（g糖）^-1 h ^-1。hycE单个突变体中不存在H ₂生成，显示Hyd-3在H ₂产生中的主要作用。在利用SCG的过程中，野生型的比生长速率为0.72±0.01 h ^-1，生物量产量为0.3 g L ^-1。基因改造，生长过程中外部参数的控制可能导致微生物H ₂延长和增强 有机废物的生产，这将更有效地满足全球可持续能源需求，从而导致移动和固定能源的多样化。