High-level expression and characterization of Aspergillus niger ATCC 1015 xylanase B in Komagataella phaffii

Abstract

Owing to the safety issues in food and feed industry, the GH11 xylanase B gene from Aspergillus niger ATCC 1015 was cloned and expressed in Komagataella phaffii. The highest xylanase B activity of 1827.19 U/ml was obtained after optimization of temperature, pH, and methanol addition through flask cultivation. The optimal temperature and pH were 55°C and 5.0, respectively, and the highest relative activity of xylanase B reached 133.20% with the addition of 10 mmol/l cupric ions. Thus, the highlevel recombinant xylanase B obtained in this study could have potential applications in food and feed industry.

Enhancement of xylanase expression byKomagataella phaffiithrough pexophagy inhibition

“…Determination of alcohol oxidase (AOX) and formate dehydrogenase (FDH) activities, ATP, ADP and AMP concentrations, and energy charge (EC) was conducted according to our previous study [11]. Xylanase B activity was ascertained as described in our previous work [9], and sorbitol determination process has been presented in an earlier study [12].…”

“…To increase sorbitol metabolism and heterologous protein production, atg30 knockout recombinant K. phaffii was constructed to inhibit pexophagy because protein Atg30, encoded by atg30, is an important component of pexophagy [8]. In our previous study, xylanase, an important food-grade enzyme used in food industry, from Aspergillus niger ATCC 1015 was expressed by recombinant K. phaffii [9]. Hence, in the present study, the yield of xylanase was enhanced for its wide applications.…”

“…The pPICZA-atg30 vector, after linearisation by DraI digestion, was transformed into K. phaffii atg30D competent cells to obtain the complement strain, which was verified by atg30 amplification using in-atg30-F and in-atg30-R as primers, and sequencing. The cloning and expression of xylanase gene (xynB) from A. niger ATCC 1015 has been described in our previous study [9].…”

“…Recently, several kinds of xylanases were discovered to endeavour a range of diverse applications [21]. Heterologous expression of xylanase is a hot topic for researchers and industrial engineers [9,22]. One important property of xylanase for its further application is its safety.…”

Biotechnological Potential of Lignocellulosic Biomass as Substrates for Fungal Xylanases and Its Bioconversion into Useful Products: A Review

“…Taking into account the safety protocols in the food and feed industries, xylanase gene B from A. niger was cloned and expressed in Komagataella phaffii and recombinant xylanase showed improved activity, i.e., 1827.19 U/mL, in methanol-mixed medium, and the purified enzyme showed optimal activity at 50 • C and pH 5.5, with a molecular mass of 18 kDa [37]. Kluyveromyces lactis was used as an expression system for the xylanase gene xynZG from Plectosphaerella cucumerina, and the recombinant enzyme exhibited a maximum activity of 115 U/mL after 72 h of incubation and a MM of 19 kDa on SDS-PAGE [38]. The successful expression of the P. citrinum xylanase gene xynA was exhibited in Yarrowia lipolytica, a fungus that produces water-soluble polysaccharides called liposan.…”