Department of Microbiology/BIOAGRO, Federal University of Viçosa (Universidade Federal de Viçosa), Viçosa-MG, Brazil.
J Basic Microbiol. 2014 Feb;54(2):133-41. doi: 10.1002/jobm.201200325. Epub 2013 Apr 2.
A number of parameters, including culture medium pH, affect growth and enzyme production by microorganisms. In the present study, the production and secretion of pectin lyase (PL) and polygalacturonase (PG) by recombinant strains of Penicillium griseoroseum cultured in mineral-buffered media (MBM; initial pH 6.8) and mineral-unbuffered medium (MUM; initial pH 6.3) were evaluated. Under these culture conditions, no change in the transcriptional levels of plg1 and pgg2 was observed. However, the levels of secreted total protein ranged from 7.80 ± 1.1 to 3.25 ± 1.50 µg ml(-1) in MBM and MUM, respectively, and were evaluated by SDS-PAGE. PL and PG enzymatic activities decreased 6.4 and 3.6 times, respectively, when P. griseoroseum was cultivated under acidic pH conditions (MUM). Furthermore, differences were observed in the hypha and mycelium morphology. These findings suggest that acidic growing conditions affect PL and PG secretion, even though the transcription and translation processes are successful. The data obtained in this study will help to establish optimal culture conditions that increase production and secretion of recombinant proteins by filamentous fungi.
许多参数，包括培养基 pH 值，都会影响微生物的生长和酶的产生。在本研究中，评估了在矿物缓冲培养基（MBM；初始 pH 值 6.8）和矿物非缓冲培养基（MUM；初始 pH 值 6.3）中培养的重组灰色青霉菌株的果胶裂解酶（PL）和聚半乳糖醛酸酶（PG）的生产和分泌情况。在这些培养条件下，plg1 和 pgg2 的转录水平没有变化。然而，通过 SDS-PAGE 评估，在 MBM 和 MUM 中分别分泌的总蛋白水平范围为 7.80±1.1 至 3.25±1.50µg ml(-1)。当在酸性 pH 条件（MUM）下培养灰色青霉时，PL 和 PG 酶活性分别下降了 6.4 倍和 3.6 倍。此外，还观察到菌丝和菌丝体形态的差异。这些发现表明，即使转录和翻译过程成功，酸性生长条件也会影响 PL 和 PG 的分泌。本研究获得的数据将有助于建立最佳的培养条件，以增加丝状真菌中重组蛋白的生产和分泌。
