Enhancement of xylanase expression by Komagataella phaffii through pexophagy inhibition
Xylanase is widely used in agriculture and food industry. To increase heterologous xylanase expression by Komagataella phaffii under the condition of mixed carbon source feeding, the atg30 gene was knocked out from this yeast to inhibit pexophagy for increasing sorbitol consumption. Komagataella phaffii atg30Δ was constructed through homologous recombination that resulted in the inhibition of pexophagy. When compared with the control, the yield of secretory xylanase increased by 4.1 ± 0.2%, 5.7 ± 0.5%, 11.8 ± 0.4% and 11.4 ± 0.7% under the conditions of 1.5% methanol and 0.5, 1, 1.5 and 2% sorbitol addition, respectively. The residual sorbitol analysis showed that sorbitol consumed by Komagataella phaffii atg30Δ increased by 121.3 ± 9.3%, 66.8 ± 15.2% and 31.2 ± 3.2% following 1, 1.5 and 2 sorbitol addition, respectively. Thus, non-methanol carbon source, co-feeding with methanol, provided more energy without pexophagy by atg30 gene knockout. Pexophagy inhibition increased the heterologous protein expression by Komagataella phaffii, which provided basis for increased yield of xylanase through pexophagy monitoring.