Xylanase production by the thermophilic mold Humicola lanuginosa in solid-state fermentation
Xylanase production by the thermophilic mold Humicola lanuginosa in solid-state fermentation
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DOI：
10.1385/abab:119:2:145
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发表时间：
2004-11-01
影响因子：
3
通讯作者：
Satyanarayana, T
中科院分区：
文献类型：
--
作者：
Kamra, P;Satyanarayana, T
在所测试的木质纤维底物中，小麦麸皮支持Humicola Lanuginosa在固态发酵(SSF)中分泌高木聚糖酶(EC 3.2.1.8)。产酶在72h达到高峰，随后下降。在底物与保湿剂比例为1：2.5(w/v)、接种量为3×10(6)个孢子/10 g麦麸、水分活度(a(W))为0.95的条件下，用自来水润湿小麦麸皮时，产酶能力很高(7832U/g干霉麸皮)。在大的珐琅托盘中培养该霉菌产生的木聚糖酶效价与烧瓶中的木聚糖酶效价相当。通过参数优化，SSF产酶能力提高了31%。固态发酵的木聚糖酶产量约为深层发酵的23倍。在以葡萄糖为唯一碳源的条件下，羊肚菌分泌的木聚糖酶的组成水平达到一个临界值。该酶是由木糖和木聚糖诱导的。在SMF中，木糖含量超过1.0%(w/v)时，酶的合成受到抑制，而在SSF中，酶的合成在3.0%(w/w)时不受影响，这表明SSF中分解代谢的抑制作用最小。
Among the lignocellulosic substrates tested, wheat bran supported a high xylanase (EC 3.2.1.8) secretion by Humicola lanuginosa in solid-state fermentation (SSF). Enzyme production reached a peak in 72 h followed by a decline thereafter. Enzyme production was very high (7832 U/g of dry moldy bran) when wheat bran was moistened with tap water at a substrate-to-moistening agent ratio of 1:2.5 (w/v) and an inoculum level of 3 x 10(6) spores/10 g of wheat bran at a water activity (a(w)) of 0.95. Cultivation of the mold in large enamel trays yielded a xylanase titer comparable with that in flasks. Parametric optimization resulted in a 31% increase in enzyme production in SSF. Xylanase production was approx 23-fold higher in SSF than in submerged fermentation (SmF). A threshold constitutive level of xylanase was secreted by H. lanuginosa in a medium containing glucose as the sole carbon source. The enzyme was induced by xylose and xylan. Enzyme synthesis was repressed beyond 1.0% (w/v) xylose in SmF, whereas it was unaffected up to 3.0% (w/w) in SSF, suggesting a minimization of catabolite repression in SSF.