Benzoic acid fermentation from starch and cellulose via a plant-like β-oxidation pathway in Streptomyces maritimus
Benzoic acid fermentation from starch and cellulose via a plant-like β-oxidation pathway in Streptomyces maritimus
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DOI：
10.1186/1475-2859-11-49
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发表时间：
2012-04-30
影响因子：
6.4
通讯作者：
Kondo, Akihiko
中科院分区：
文献类型：
--
作者：
Noda, Shuhei;Kitazono, Eiichi;Kondo, Akihiko
背景：苯甲酸是应用最广泛的芳香化合物之一。尽管其用途广泛且结构简单，但利用微生物生产苯甲酸尚未见报道。链霉菌是需氧、革兰氏阳性、形成菌丝的土壤细菌，已知能产生多种由芳香残基组成的抗生素。海洋单胞菌具有复杂的氨基酸修饰途径，可以作为一种新的平台微生物生产芳香基化合物。本研究以海棠为原料进行了苯甲酸盐发酵。为了提高以纤维素为碳源的苯甲酸酯产率，我们构建了分泌内切葡聚糖酶的海苔菌。结果：以葡萄糖、纤维素二糖和淀粉为碳源培养4天后，苯甲酸酯的最高水平分别达到257、337和460 mg/l。与lividans和coelicolor相比，海棠表达了β -葡萄糖苷酶和较高的淀粉酶保留活性。此外，为了从纤维素材料中有效地生产苯甲酸酯，我们构建了分泌内切葡聚糖酶的S. maritimus。这种转化有效地降解了磷酸膨胀纤维素（PASC），然后产生125 mg/l的苯甲酸酯。结论：野生海棠通过类似植物的β -氧化途径产生苯甲酸酯，并能吸收多种碳源产生苯甲酸酯。为了促进纤维素的降解和提高纤维素中苯甲酸酯的产量，我们构建了分泌内切葡聚糖酶的s.m itimus。利用这种转化，我们还演示了从纤维素中直接发酵苯甲酸酯。为了进一步提高苯甲酸酯的生产效率，未来需要提高l -苯丙氨酸的利用率。
Background: Benzoic acid is one of the most useful aromatic compounds. Despite its versatility and simple structure, benzoic acid production using microbes has not been reported previously. Streptomyces are aerobic, Gram-positive, mycelia-forming soil bacteria, and are known to produce various kinds of antibiotics composed of many aromatic residues. S. maritimus possess a complex amino acid modification pathway and can serve as a new platform microbe to produce aromatic building-block compounds. In this study, we carried out benzoate fermentation using S. maritimus. In order to enhance benzoate productivity using cellulose as the carbon source, we constructed endo-glucanase secreting S. maritimus.Results: After 4 days of cultivation using glucose, cellobiose, or starch as a carbon source, the maximal level of benzoate reached 257, 337, and 460 mg/l, respectively. S. maritimus expressed beta-glucosidase and high amylase-retaining activity compared to those of S. lividans and S. coelicolor. In addition, for effective benzoate production from cellulosic materials, we constructed endo-glucanase-secreting S. maritimus. This transformant efficiently degraded the phosphoric acid swollen cellulose (PASC) and then produced 125 mg/l benzoate.Conclusions: Wild-type S. maritimus produce benzoate via a plant-like beta-oxidation pathway and can assimilate various carbon sources for benzoate production. In order to encourage cellulose degradation and improve benzoate productivity from cellulose, we constructed endo-glucanase-secreting S. maritimus. Using this transformant, we also demonstrated the direct fermentation of benzoate from cellulose. To achieve further benzoate productivity, the L-phenylalanine availability needs to be improved in future.