Studying the effects of endogenous and exogenous histidine supplementation on Pichia pastoris cultured in YPA

A histidine prototrophic strain achieves A600 three-four fold higher than a histidine auxotroph when cultured in nutrient rich media YPA, which is abundant in amino acids. This retaded growth of histidine auxotroph in YPA can also be rescued by supplementing media with exogenous histidine. Here, we aim to study the transcriptomic changes associated with culturing of histidine auxotroph and prototroph in YPA and also the effects of histidine addition to the culture medium of histidine auxotroph. Wild type cells were cultured in nutrient rich medium containing yeast extract, peptone and acetate as a carbon source (YPA), alone or supplemented with 650 uM histidiene. Cells were harvested after 24 hours followed by RNA preparation using QIAGEN RNEASY Mini Kit which was then subjected to RNA-SEQ.