Fontana J D, Chocial M B, Baron M, Guimaraes M F, Maraschin M, Ulhoa C, Florêncio J A, Bonfim T M
LQBB-Biomass Chemo Biotechnology Laboratory/Biochemistry/UFPR, P.O. Box 19046 (81531-990), Curitiba-PR, Brazil.
Appl Biochem Biotechnol. 1997 Spring;63-65:305-14. doi: 10.1007/BF02920432.
Astaxanthin is a diketo-dihydroxy-carotenoid produced by Phaffia rhodozyma, a basidiomicetous yeast. A low-cost fermentation medium consisting of raw sugarcane juice and urea was developed to exploit the active sucrolytic/urelolytic enzyme apparatus inherent to the yeast. As compared to the beneficial effect of 0.1 g% urea, a ready nitrogen source, mild phosphoric pre inversion of juice sucrose to glucose and fructose, promptly fermentable carbon sources, resulted in smaller benefits. Corn steep liquor (CSL) was found to be a valuable supplement for both yeast biomass yield (9.2 g dry cells/L) and astaxanthin production (1.3 mg/g cells). Distillery effluent (vinace), despite only a slightly positive effect on yeast growth, allowed for the highest pigment productivity (1.9 mg/g cells). Trace amounts of Ni2 (1 mg/L, as a cofactor for urease) resulted in controversial effects, namely, biomass decrease and astaxanthin increase, with no effect on the release (and uptake) of ammonium ion from urea. Since the synthesized astaxanthin is associated with the yeast cell and the pigment requires facilitated release for aquaculture uses (farmed fish meat staining), an investigation of the yeast cell wall was undertaken using detergent-treated cells. The composition of the rigid yeast envelope was found to be heterogeneous. Its partial acid or enzymatic depolymerization revealed glucose and xylose as common monomeric units of the cell-wall glycopolymers. Yeast cell-wall partial depolymerization with appropriate hydrolases may improve the pigment bioavailability for captive aquatic species and poultry.
虾青素是一种由红法夫酵母（一种担子菌酵母）产生的二酮 - 二羟基类胡萝卜素。开发了一种由原甘蔗汁和尿素组成的低成本发酵培养基，以利用酵母固有的活性蔗糖分解/尿素分解酶装置。与现成的氮源0.1 g%尿素的有益效果相比，将果汁蔗糖轻度磷酸预转化为葡萄糖和果糖（即易于发酵的碳源）所带来的益处较小。发现玉米浆（CSL）对酵母生物量产量（9.2 g干细胞/L）和虾青素产量（1.3 mg/g细胞）都是一种有价值的补充剂。酿酒厂废水（vinace）尽管对酵母生长只有轻微的积极影响，但却能实现最高的色素生产率（1.9 mg/g细胞）。痕量的Ni2（1 mg/L，作为脲酶的辅因子）产生了有争议的影响，即生物量减少而虾青素增加，对尿素中铵离子的释放（和吸收）没有影响。由于合成的虾青素与酵母细胞相关联，并且该色素需要促进释放以供水产养殖使用（养殖鱼肉染色），因此使用经洗涤剂处理的细胞对酵母细胞壁进行了研究。发现坚硬的酵母包膜的组成是异质的。其部分酸解或酶解解聚揭示葡萄糖和木糖是细胞壁糖聚合物的常见单体单元。用适当的水解酶对酵母细胞壁进行部分解聚可能会提高圈养水生物种和家禽对色素的生物利用率。
