枯草芽孢杆菌KCX006产生无β-木糖苷酶的内切木聚糖酶和多种木聚糖去分支酶在固态发酵中生产低聚木糖。
Production of xylooligosaccharides in SSF by Bacillus subtilis KCX006 producing β-xylosidase-free endo-xylanase and multiple xylan debranching enzymes.
作者信息
Reddy Shyam Sunder, Krishnan Chandraraj
机构信息
a Department of Biotechnology , Indian Institute of Technology Madras , Chennai , India.
出版信息
Prep Biochem Biotechnol. 2016;46(1):49-55. doi: 10.1080/10826068.2014.970694.
Xylanase and xylooligosaccharides (XOS) are employed in food and feed industries. Though xylanase production from lignocellulosic materials (LCMs) by solid-state fermentation (SSF) is well known, the XOS formed during growth is not recovered due to its conversion to xylose by β-xylosidase and subsequent bacterial metabolism. A new strain, Bacillus subtilis KCX006, was exceptionally found to synthesize β-xylosidase-free endo-xylanase and multiple xylan debranching enzymes constitutively in the presence of LCMs. Absence of β-xylosidase resulted in accumulation of XOS during growth of KCX006 on LCMs. Therefore, this strain was used for simultaneous production of xylanase and XOS from agro-residues in solid-state fermentation (SSF). Partial purification of XOS from culture supernatant using activated charcoal followed by high-performance liquid chromatography (HPLC) analysis showed xylobiose to xylotetraose formed as the major products. Among various LCM substrates, wheat bran and groundnut oil-cake supported highest xylanase and XOS production at 2158 IU/gdw and 24.92 mg/gdw, respectively. The levels of xylanase and XOS were improved by 1.5-fold (3102 IU/gdw) and 1.9-fold (48 mg/gdw), respectively, by optimization of culture conditions.
木聚糖酶和低聚木糖(XOS)被应用于食品和饲料行业。虽然通过固态发酵(SSF)从木质纤维素材料(LCMs)生产木聚糖酶是众所周知的,但生长过程中形成的XOS由于被β-木糖苷酶转化为木糖并随后被细菌代谢而无法回收。意外发现一种新菌株枯草芽孢杆菌KCX006在存在LCMs的情况下可组成型合成无β-木糖苷酶的内切木聚糖酶和多种木聚糖脱支酶。β-木糖苷酶的缺失导致KCX006在LCMs上生长期间XOS的积累。因此,该菌株被用于在固态发酵(SSF)中从农业残留物同时生产木聚糖酶和XOS。使用活性炭从培养上清液中部分纯化XOS,随后进行高效液相色谱(HPLC)分析,结果表明形成以木二糖到木四糖为主的产物。在各种LCM底物中,麦麸和花生饼分别支持最高的木聚糖酶和XOS产量,分别为2158 IU/gdw和24.92 mg/gdw。通过优化培养条件,木聚糖酶和XOS的水平分别提高了1.5倍(3102 IU/gdw)和1.9倍(48 mg/gdw)。