毕赤酵母单宁酶工程菌在固、液发酵中的性质差异分析

探究固、液发酵方式在重组毕赤酵母单宁酶工程菌的形态、产酶量及酶学特性等方面的差异。研究发现,重组菌株在固、液发酵方式下表现出了较大差异。固态发酵条件下,重组菌株能够积累更多的生物量,当培养48 h后积累的生物量比液态发酵高22.3%;经电镜分析发现,固态条件下,重组菌株个体之间更容易出现聚集,并伴随着有生物膜的产生;在不同甲醇体积分数诱导下,固、液发酵的重组菌株的产酶量均出现了先升高后降低的趋势,而诱导两者最高产酶量的甲醇体积分数却存在差异,分别是2%和3%。进一步研究发现,固、液发酵条件下,重组菌株发酵的单宁酶酶学性质也存在一定差异,固、液态发酵单宁酶的最适反应温度分别为30 ℃和为20 ℃,且酶的热稳定性也有一定提高,其余酶学性质差异不显著。经十二烷基硫酸钠-聚丙烯酰氨凝胶电泳分析发现,固态发酵生产的单宁酶存在不同的修饰,这可能是造成上述性质差异的原因之一。综上所述,本研究探究了固、液发酵条件下,重组单宁酶毕赤酵母菌株生长及产酶特性的差异,为高效制备单宁酶提供了一定的理论指导。

Effect of Fermentation System on the Production and Properties of Recombinant Pichia pastoris Tannase

This experiment was conducted to investigate the effects of solid (SSF) and liquid-state fermentation (LSF) on the morphology and the production and enzymatic properties of tannase of recombinant Pichia pastoris. It was found that there were large differences between SSF and LSF in terms of the bacterial morphology and the production and enzymatic properties of tannase. The recombinant strain had a higher biomass accumulation in SSF, which was 22.3% higher than that in SMF after 48 h incubation. From scanning electron microscopic (SEM) analysis, it was found that individual cells of the recombinant strain were more prone to aggregation, accompanied by the emergence of biofilm in SSF. For both SSF and LSF, the enzyme production increased first and then decreased with methanol concentration, reaching its maximum at methanol concentrations of 2% and 3%, respectively. Furthermore, tanninases produced in SSF and LSF had different enzymatic properties, and their optimum temperatures were 30 and 20 ℃, respectively. The thermal stability of the former was slightly weaker than that of the latter, whereas no significant difference was found in any other enzymatic property tested. In addition, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis showed that tanninase produced in SSF was modified, which may account for the above differences. In conclusion, the findings of this can provide a theoretical foundation for the efficient preparation of tannase.