利用农业废弃物碳源的红法夫酵母生产虾青素研究进展

利用红法夫酵母产虾青素工艺具有绿色、安全、低成本等优点,但培养红法夫酵母的培养基(尤其是碳源)成本是制约该工艺实现大规模生产的主要因素之一。传统的利用纯糖如葡萄糖、蔗糖、木糖等作为红法夫酵母生产虾青素的碳源,效果虽好,但因其价格较高,仅适用于实验室研究和小型发酵生产,不适于大规模工业化生产。如何寻找来源广、价廉且发酵效果好的碳源,降低虾青素的生产成本是发展虾青素产业亟待解决的课题。利用廉价且来源广泛的原料如水果类原料、糖质原料、甘油及废弃木质纤维素类原料等作为碳源能有效降低成本。但这些原料都存在一些问题,比如水果类原料存在季节性及地域性限制,糖蜜类原料供应稳定性方面存在问题,甘油类原料杂质多且存在食品安全隐患,木质纤维素类原料来源广泛、价格低廉,不存在占用耕地等问题,是最有希望用于规模化低成本发酵生产虾青素的原料,但其利用存在一些技术瓶颈。该文介绍了目前利用红法夫酵母生产虾青素的基本情况,并系统地对国内外不同碳源条件下利用红法夫酵母生产虾青素的研究状况进行了综述、比较及分析。最后,对利用红法夫酵母生产虾青素在碳源方面的未来发展趋势及重点研究方向进行了展望。

Review on astaxanthin production from agricultural wastes by Phaffia rhodozyma

Astaxanthin production by Phaffia rhodozyma is environmentally friendly, safe, and cost effect, but the cost of the medium for culture of Phaffia rhodozyma especially carbon sources is one of the major factors that constrain this process from achieving massive production.Using cheap and widely sourced raw materials such as saccharides, low-value starch, glycerol, and waste lignocelluloseas carbon sources can effectively reduce the cost.In this paper, we summarized the current use of Phaffia rhodozyma to produce astaxanthin, and systematically reviewed, compared, and analyzed domestic and foreign studies on astaxanthin production by Phaffia rhodozyma using different carbon sources.Conventional use of pure sugar such as glucose, sucrose and xylose as a carbon source for astaxanthin production by Phaffia rhodozyma has good effects, but is applicable only in laboratory studies and in small-scale fermentation due to its high costs.Fruit, when used as a carbon source for astaxanthin production by Phaffia rhodozyma, has wide resources and is easy to pretreat, suitable for microbial growth and widely used for astaxanthin production.However, due to the seasonal fluctuations and geographical limitations on fruit, it is difficult to promote the use of fruit as a carbon source for astaxanthinproduction by Phaffia rhodozyma on a large scale.Molasses, which has a high sugar content and is subject to a wide supply, is a good carbon source.However, using it for astaxanthin production may result in competing resource with other industries (such as fuel alcohol).Therefore, the stability of its supply cannot be ensured.When glycerin is used as a carbon source for astaxanthin production by Phaffia rhodozyma, not only can Phaffia rhodozyma grow well, but astaxanthin also accumulates steadily in the body of Phaffia rhodozyma.However, it is difficult to obtain high-purity glycerin.Crude glycerol generated during biodiesel production contains a lot of impurities (such as methanol), which can significantly affect microbial growth and astaxanthin accumulation, and may also have food safety issues.Lignocellulose has a variety of sources, which primarily include some agricultural or forest waste such as straw, wood chips, and corn fiber.Currently, a popular application of lignocellulose is the preparation of fuel ethanol, but the utilization of xylose poses a major obstacle to the preparation of fuel ethanol using lignocellulose.Phaffia rhodozyma can make efficient utilization of xylose.Therefore, lignocellulose is a very promising raw material that can be used for large-scale and low-cost fermentative astaxanthin production.However, its utilization suffers from the following technological bottlenecks: complicated pre-treatment; the inhibitory substances to microbial growth produced from acid hydrolysis need to be detoxified, which can result in a decrease in astaxanthin production efficiency; and, the high cost and inefficiency of cellulase used for hydrolyzing lignocellulose, which makes it costly to prepare reduced sugars using lignocellulose and produce astaxanthin.Based on these, future studies on the carbon sources for astaxanthin production by Phaffia rhodozyma should focus on the development of more cheap carbon sources or the comprehensive utilization of multiple carbon sources, while aiming to overcome technological bottlenecks that restrict the use of lignocellulose as a carbon source.Finally, the future trends in and key research directions for the carbon sources used for astaxanthin production by Phaffia rhodozyma were envisaged.