Engineering the xylose metabolism in Schizochytrium sp. to improve the utilization of lignocellulose.
Engineering the xylose metabolism in Schizochytrium sp. to improve the utilization of lignocellulose.
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工程裂殖壶菌中的木糖代谢。
DOI：
10.1186/s13068-022-02215-w
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发表时间：
2022-10-26
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影响因子：
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背景
Schizochytrium sp.是一种异养产油微生物，可以有效地产生脂质。然而，由于高成本的培养基，使用裂殖壶菌属的工业化生产大宗化学品仍然在经济上不可行。用廉价且可再生的木质纤维素代替葡萄糖是降低生产成本的非常有前途的方法，但是裂殖壶菌不能有效地代谢木糖，木糖是木质纤维素生物质中的主要戊糖。
结果
为了提高裂殖壶菌对木质纤维素的利用率，我们克隆了编码参与木糖代谢的酶的基因并对其进行了功能表征。结果表明，内源木糖还原酶和木酮糖激酶基因具有相应的功能活性。此外，尝试通过使用基因工程技术引入外源木糖醇脱氢酶/木糖异构酶来构建能够有效利用木糖的裂殖壶菌属菌株;然而，引入异源木糖醇脱氢酶没有产生利用木糖的工程菌株，而引入木糖异构酶产生了利用木糖的工程菌株。结果表明，工程菌308-XI在60 h的发酵过程中可消耗8.2 g/L木糖。当异源木糖异构酶和木酮糖激酶同时过表达时，木糖消耗进一步升高至11.1g/L。此外，使用含有葡萄糖和木糖的木质纤维素水解产物培养308-XI-XK（S），分别产生22.4g/L的干细胞重量和5.3g/L的总脂质滴度，与野生型相比增加了42.7%和30.4%。
结论
本研究表明，改造裂殖壶菌高效利用木糖，有利于提高其对木质纤维素的利用率，从而降低工业化油脂生产的成本。
Background
Schizochytrium sp. is a heterotrophic, oil-producing microorganism that can efficiently produce lipids. However, the industrial production of bulk chemicals using Schizochytrium sp. is still not economically viable due to high-cost culture medium. Replacing glucose with cheap and renewable lignocellulose is a highly promising approach to reduce production costs, but Schizochytrium sp. cannot efficiently metabolize xylose, a major pentose in lignocellulosic biomass.
Results
In order to improve the utilization of lignocellulose by Schizochytrium sp., we cloned and functionally characterized the genes encoding enzymes involved in the xylose metabolism. The results showed that the endogenous xylose reductase and xylulose kinase genes possess corresponding functional activities. Additionally, attempts were made to construct a strain of Schizochytrium sp. that can effectively use xylose by using genetic engineering techniques to introduce exogenous xylitol dehydrogenase/xylose isomerase; however, the introduction of heterologous xylitol dehydrogenase did not produce a xylose-utilizing engineered strain, whereas the introduction of xylose isomerase did. The results showed that the engineered strain 308-XI with an exogenous xylose isomerase could consume 8.2 g/L xylose over 60 h of cultivation. Xylose consumption was further elevated to 11.1 g/L when heterologous xylose isomerase and xylulose kinase were overexpressed simultaneously. Furthermore, cultivation of 308-XI-XK(S) using lignocellulosic hydrolysates, which contained glucose and xylose, yielded a 22.4 g/L of dry cell weight and 5.3 g/L of total lipid titer, respectively, representing 42.7 and 30.4% increases compared to the wild type.
Conclusion
This study shows that engineering of Schizochytrium sp. to efficiently utilize xylose is conducive to improve its utilization of lignocellulose, which can reduce the costs of industrial lipid production.
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影响因子：
3.2
作者：
Kujawska, Natalia;Talbierz, Szymon;Zielinski, Marcin
通讯作者：
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DOI：
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DOI：
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发表时间：
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期刊：
MEMBRANE BIOGENESIS: METHODS AND PROTOCOLS
影响因子：
--
作者：
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通讯作者：
de Gier, Jan-Willem