Braun-Galleani Stephanie, Henríquez Maria-José, Nesbeth Darren N
Department of Biochemical Engineering, University College London, Bernard Katz Building, London, WC1E 6BT, United Kingdom.
Heliyon. 2019 Aug 20;5(8):e02338. doi: 10.1016/j.heliyon.2019.e02338. eCollection 2019 Aug.
We have engineered strain BG-10 of the methylotrophic yeast for use as an effective whole cell biocatalyst. We introduced into the yeast a transgene encoding a ω-transaminase for transcription in response to methanol induction. The strain was then assessed with respect to its growth performance and biotransformation of a fed ketoalcohol substrate to an amino-alcohol. In the resultant strain, BG-TAM, methanol induction did not compromise cell growth. Successful bioconversion of fed substrates to the by-product, acetophenone, indicated transaminase activity in shake flask-cultivated BG-TAM cells. We then used bioreactor cultivation to exploit the high levels of biomass achievable by . In a 900 μL reaction the BG-TAM strain at OD = 1024 achieved up to 0.41 mol mol (mol mol ) yield on substrate (Yp/s) for production of 1-methyl-3-phenylpropylamine and a space time yield (STY) of 0.29 g L h for production of 2-amino-1,3,4-butanetriol. We have shown that transamination, an important step for bespoke synthesis of small molecule medicines, is biologically realisable using enzymes with a broad substrate range, such as ω-transaminases, within living yeast cells that are fed low-cost substrates for bioconversion.
我们构建了甲基营养型酵母菌株BG-10,用作有效的全细胞生物催化剂。我们将一个编码ω-转氨酶的转基因导入酵母,使其在甲醇诱导下进行转录。然后评估该菌株的生长性能以及将补料的酮醇底物生物转化为氨基醇的能力。在所得的BG-TAM菌株中,甲醇诱导并未损害细胞生长。补料底物成功生物转化为副产物苯乙酮,表明摇瓶培养的BG-TAM细胞具有转氨酶活性。然后,我们利用生物反应器培养来利用其可实现的高生物量水平。在900μL反应中,OD = 1024的BG-TAM菌株生产1-甲基-3-苯基丙胺时底物产率(Yp/s)高达0.41 mol/mol(mol/mol),生产2-氨基-1,3,4-丁三醇时空产率(STY)为0.29 g L-1 h-1。我们已经表明,转氨作用是定制合成小分子药物的重要步骤,在以低成本底物进行生物转化的活酵母细胞内,使用具有广泛底物范围的酶(如ω-转氨酶)在生物学上是可以实现的。