Abstract This paper evaluated the ability of Pseudomonas fluorescens to leach gold from waste printed circuit boards (WPCBs). Gold was recovered as gold-cyanide complex and cyanide was produced by Pseudomonas fluorescens. In this paper, the effect of pH on gold leaching efficiency was studied, the P.fluorescens was domesticated to grow at higher pH (pH 8 and 9), and the concentration of cyanide ions (CN−) available for bioleaching was increased in alkaline pH. The results showed that at 0.67% w/v pulp density of pretreated waste printed circuit boards powder, mutated bacteria attained gold biorecovery of 27% at pH 9, while the unadapted bacteria only 23% of bioleaching efficiency was achieved. Results revealed that bioleaching efficiency of gold from waste printed circuit boards decreased with the increase of pulp density, and 0.33% w/v pulp density had the maxnium influence to bioleaching efficiency of gold, which could reach 42%. In the two-step bioleaching process, the initial amounts of bacteria had a certain impact on the leaching efficiency, and 3.33% v/v of the initial bacterial liquid was a suitable addition. The type of substrate also affected the leaching bioleaching efficiency. The leaching efficiency in the later stage of gold leaching will be greatly improved to 54%, when glycine and methionine were added to the medium for cyanide production. This may be due to positive effect by the methionine, which could regulate the glycine pool of the cells.

中文翻译：

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耐碱荧光假单胞菌从废印刷电路板中生物浸出金

摘要 本文评估了荧光假单胞菌从废印刷电路板（WPCBs）中浸出金的能力。金以金-氰化物络合物的形式回收，氰化物由荧光假单胞菌产生。在本文中，研究了 pH 值对金浸出效率的影响，将荧光假单胞菌驯化为在较高 pH 值（pH 8 和 9）下生长，并在碱性条件下增加了可用于生物浸出的氰化物离子 (CN−) 浓度酸碱度。结果表明，在预处理废印刷电路板粉末的纸浆密度为 0.67% w/v 时，突变细菌在 pH 9 下获得了 27% 的金生物回收率，而未适应的细菌仅实现了 23% 的生物浸出效率。结果表明，废印刷电路板中金的生物浸出效率随着纸浆密度的增加而降低，0. 33% w/v的矿浆密度对金的生物浸出效率影响最大，可达42%。在两步法生物浸出过程中，初始菌量对浸出效率有一定影响，初始菌液的加入量为3.33% v/v为宜。底物的类型也影响浸出生物浸出效率。在生产氰化物的培养基中加入甘氨酸和蛋氨酸，浸金后期的浸出效率将大大提高至54%。这可能是由于蛋氨酸的积极作用，它可以调节细胞的甘氨酸库。33% v/v 的初始菌液是合适的添加量。底物的类型也影响浸出生物浸出效率。在生产氰化物的培养基中加入甘氨酸和蛋氨酸，浸金后期的浸出效率将大大提高至54%。这可能是由于蛋氨酸的积极作用，它可以调节细胞的甘氨酸库。33% v/v 的初始菌液是合适的添加量。底物的类型也影响浸出生物浸出效率。在生产氰化物的培养基中加入甘氨酸和蛋氨酸，浸金后期的浸出效率将大大提高至54%。这可能是由于蛋氨酸的积极作用，它可以调节细胞的甘氨酸库。