Gervais T R, Carta G, Gainer J L
Department of Chemical Engineering, University of Virginia, Charlottesville, Virginia 22904-4741, USA.
Biotechnol Prog. 2000 Mar-Apr;16(2):208-12. doi: 10.1021/bp0000050.
The effect of aeration during cell growth on the subsequent reduction of 2-hexanone and 2-octanone by yeast cells entrapped in calcium alginate beads was studied. The reactions were conducted using 2-propanol as a sacrificial substrate to regenerate the cofactor NAD(H), and a mixture of (S)- and (R)-alcohols was produced. The use of strictly aerobic conditions when growing the cells resulted in the highest initial reaction rates, as well as the production of only a single product (i.e., the enantiomeric excess of the (S)-alcohols was 1.0). However, initial reaction rates decreased proportionally with fermentation time regardless of whether the yeast were grown aerobically or under both aerobic and anaerobic conditions. The data also suggest that it is the aerobic (or anaerobic) condition, rather than the cell growth phase, which is responsible for the results seen.
研究了细胞生长过程中的通气对包埋在海藻酸钙珠中的酵母细胞随后还原2-己酮和2-辛酮的影响。反应以2-丙醇作为牺牲底物进行，以再生辅因子NAD(H)，并产生了(S)-醇和(R)-醇的混合物。在细胞生长时使用严格的好氧条件导致了最高的初始反应速率，并且只产生单一产物（即(S)-醇的对映体过量为1.0）。然而，无论酵母是在好氧条件下生长还是在好氧和厌氧条件下生长，初始反应速率都与发酵时间成比例下降。数据还表明，导致所观察到结果的是好氧（或厌氧）条件，而不是细胞生长阶段。
