The gas-to-liquid (GTL) process generates considerable amounts of wastewater that are highly acidic and characterized by its high chemical oxygen demand (COD) content, due to the presence of several organic pollutants, such as alcohols, ketones, aldehydes, and fatty acids. The presence of these organics in the process water may lead to adverse effect on the environment and aquatic life. Thus, it is necessary to reduce the COD content of GTL process water to an acceptable limit before discharging or reusing the treated water. Due to several advantages, biological treatment is often utilized as the main step in GTL process water treatment plants. In order to have a successful biotreatment process, it is required to choose effective and suitable bacterial strains that have the ability to degrade the organic pollutants in GTL process water. In this work, bacterial strains were isolated from the GTL process water, identified by 16S rRNA gene sequencing and then used in the biodegradation process. The detailed identification of the strains confirmed the presence of three organics-degrading bacteria identified as Alcaligenes faecalis, Stenotrophomonas sp., and Ochrobactrum sp. Furthermore, biodegradation experiments were carried out and confirmed that the pure culture as well as the mixed culture consortium of the bacterial strains has the ability to reduce the organic pollutants in GTL process water. However, the growth rate and biodegradation efficiency depend on the type of strains and the initial COD content. Indeed, the removal percentage and growth rate were enhanced after 7 days for all cultures and resulted in COD reduction up to 60%. Moreover, the mixed culture of bacterial strains can tolerate and treat GTL process water with a variety of ranges of COD contents.

中文翻译：

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气转液工艺水中有机物降解细菌的分离和鉴定

气转液 (GTL) 过程会产生大量的高酸性废水，其特点是化学需氧量 (COD) 含量高，这是由于存在多种有机污染物，如醇、酮、醛和脂肪酸。工艺用水中存在这些有机物可能会对环境和水生生物造成不利影响。因此，在排放或再利用处理过的水之前，有必要将 GTL 工艺用水的 COD 含量降低到可接受的限度。由于几个优点，生物处理通常被用作 GTL 工艺水处理厂的主要步骤。为了获得成功的生物处理过程，需要选择有效且合适的菌株，这些菌株具有降解 GTL 工艺水中有机污染物的能力。在这项工作中，细菌菌株从 GTL 工艺水中分离出来，通过 16S rRNA 基因测序进行鉴定，然后用于生物降解过程。菌株的详细鉴定证实了三种有机物降解细菌的存在，它们被鉴定为粪产碱菌、狭养单胞菌和 Ochrobactrum sp。此外，还进行了生物降解实验，证实细菌菌株的纯培养和混合培养联合体具有减少GTL工艺水中有机污染物的能力。然而，生长速率和生物降解效率取决于菌株的类型和初始 COD 含量。实际上，所有培养物的去除百分比和生长速率在 7 天后都得到了提高，并导致 COD 降低了 60%。而且，