BACKGROUND Marine macroalgae Gelidium amansii is a promising feedstock for production of sustainable biochemicals to replace petroleum and edible biomass. Different from terrestrial lignocellulosic biomass, G. amansii is comprised of high carbohydrate content and has no lignin. In previous studies, G. amansii biomass has been exploited to obtain fermentable sugars along with suppressing 5-hydroxymethylfurfural (HMF) formation for bioethanol production. In this study, a different strategy was addressed and verified for dual production of D-galactose and HMF, which were subsequently oxidized to D-galactonic acid and 5-hydroxymethyl-2-furancarboxylic acid (HMFCA) respectively via Pseudomonas putida. RESULTS G. amansii biomass was hydrolyzed by dilute acid to form D-galactose and HMF. The best result was attained after pretreatment with 2% (w/w) HCl at 120 °C for 40 min. Five different Pseudomonas sp. strains including P. putida ATCC 47054, P. fragi ATCC 4973, P. stutzeri CICC 10402, P. rhodesiae CICC 21960, and P. aeruginosa CGMCC 1.10712, were screened for highly selective oxidation of D-galactose and HMF. Among them, P. putida ATCC 47054 was the outstanding suitable biocatalyst converting D-galactose and HMF to the corresponding acids without reduced or over-oxidized products. It was plausible that the pyrroloquinoline quinone-dependent glucose dehydrogenase and undiscovered molybdate-dependent enzyme(s) in P. putida ATCC 47054 individually played pivotal role for D-galactose and HMF oxidation. Taking advantage of its excellent efficiency and high selectivity, a maximum of 55.30 g/L D-galactonic acid and 11.09 g/L HMFCA were obtained with yields of 91.1% and 98.7% using G. amansii hydrolysates as substrate. CONCLUSIONS Valorization of G. amansii biomass for dual production of D-galactonic acid and HMFCA can enrich the product varieties and improve the economic benefits. This study also demonstrates the perspective of making full use of marine feedstocks to produce other value-added products.

中文翻译：

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通过化学生物学方法对石花菜进行 D-半乳糖酸和 5-羟甲基-2-呋喃甲酸双重生产的价值评估。


背景技术海洋大型藻类石花菜是用于生产可持续生物化学品以替代石油和可食用生物质的有前景的原料。与陆地木质纤维素生物质不同，G. amansii 含有高碳水化合物且不含木质素。在之前的研究中，G. amansii 生物质已被用来获取可发酵糖，同时抑制 5-羟甲基糠醛 (HMF) 的形成，用于生物乙醇生产。在这项研究中，提出并验证了一种不同的策略来双重生产 D-半乳糖和 HMF，随后通过恶臭假单胞菌分别氧化为 D-半乳糖酸和 5-羟甲基-2-呋喃甲酸 (HMFCA)。结果 G. amansii 生物质被稀酸水解形成 D-半乳糖和 HMF。用 2% (w/w) HCl 在 120 °C 预处理 40 分钟后获得最佳结果。五种不同的假单胞菌属。筛选了 P. putida ATCC 47054、P. fragi ATCC 4973、P. Stutzeri CICC 10402、P. rhodesiae CICC 21960 和 P. aeruginosa CGMCC 1.10712 等菌株，用于 D-半乳糖和 HMF 的高度选择性氧化。其中，恶臭假单胞菌ATCC 47054是将D-半乳糖和HMF转化为相应的酸而没有还原或过度氧化产物的杰出合适的生物催化剂。恶臭假单胞菌 ATCC 47054 中的吡咯喹啉醌依赖性葡萄糖脱氢酶和未发现的钼酸盐依赖性酶可能分别对 D-半乳糖和 HMF 氧化发挥关键作用。利用其优异的效率和高选择性，以G. amansii水解液为底物，最高可得到55.30 g/L D-半乳糖酸和11.09 g/L HMFCA，收率分别为91.1%和98.7%。结论 G 的价值评估。 阿曼西生物质双产D-半乳酸和HMFCA可丰富产品品种，提高经济效益。这项研究还展示了充分利用海洋原料生产其他增值产品的前景。