Ashokkumar Balasubramaniem, Gunasekaran Paramasamy
Centre for Advanced Studies in Functional Genomics, School of Biological Sciences, Madurai Kamaraj University, Madurai 625 021, India.
Indian J Exp Biol. 2002 Sep;40(9):1032-7.
Aspergillus niger produces extracellular beta-fructofuranosidase under submerged (SmF) and solid state fermentation (SSF) conditions. After UV mutagenesis of conidiospores of A. niger, 2-deoxyglucose (10 g/l) resistant mutants were isolated on Czapek's minimal medium containing glycerol as a carbon source and the mutants were examined for improved production of beta-fructofuranosidase in SmF and SSF conditions. One of such mutant DGRA-1 overproduced beta-fructofuranosidase in both SmF and SSF conditions. In SmF, the mutant DGRA-1 showed higher beta-fructofuranosidase productivity (110.8 U/l/hr) than the wild type (48.3 U/l/hr). While in SSF the same strain produced 322 U/l/hr of beta-fructofuranosidase, 2 times higher than that of wild type (154.2 U/l/hr). In SmF, both wild type and mutants produced relatively low level of beta-fructofuranosidase in medium containing sucrose with glucose than from the sucrose medium. However in SSF, the DGRA-1 mutant grown in sucrose and sucrose+ glucose did not show any difference with respect to beta-fructofuranosidase production. These results indicate that the catabolite repression of beta-fructofuranosidase synthesis is observed in SmF whereas in SSF such regulation was not prominent.
黑曲霉在深层发酵（SmF）和固态发酵（SSF）条件下可产生胞外β-呋喃果糖苷酶。对黑曲霉分生孢子进行紫外线诱变后，在以甘油作为碳源的察氏基本培养基上分离出对2-脱氧葡萄糖（10 g/l）具有抗性的突变体，并检测这些突变体在深层发酵和固态发酵条件下β-呋喃果糖苷酶产量的提高情况。其中一个突变体DGRA-1在深层发酵和固态发酵条件下均过量产生β-呋喃果糖苷酶。在深层发酵中，突变体DGRA-1的β-呋喃果糖苷酶生产效率（110.8 U/l/hr）高于野生型（48.3 U/l/hr）。而在固态发酵中，同一菌株产生322 U/l/hr的β-呋喃果糖苷酶，比野生型（154.2 U/l/hr）高出2倍。在深层发酵中，野生型和突变体在含有蔗糖与葡萄糖的培养基中产生的β-呋喃果糖苷酶水平均相对低于蔗糖培养基。然而在固态发酵中，在蔗糖以及蔗糖 + 葡萄糖中生长的DGRA-1突变体在β-呋喃果糖苷酶生产方面没有表现出任何差异。这些结果表明，在深层发酵中观察到了β-呋喃果糖苷酶合成的分解代谢物阻遏现象，而在固态发酵中这种调控并不显著。
