Prospective evaluation of xylitol production using Dabaryomyces hansenii var hansenii, Pachysolen tannophilus, and Candida guillermondii with sustainable agricultural residues

Abstract

In this study, agro-wastes, including corncob, rice straw, and wheat straw, were used as substrate for xylitol production using Dabaryomyces hansenii var hansenii, Pachysolen tannophilus, and Candida guillermondii. The experiments were performed using batch fermentation using hemicellulose hydrolyzate as substrate under optimum levels of the screened significant nutrients and process variables. Screening and optimization were carried out for all the systems using statistical methods based on experimental designs. Kinetics and modeling for xylitol production were developed using the logistic model for microbial growth, substrate utilization kinetics for the substrate utilization, and Luedeking-Piret model for the product formation. The model parameters were compared for all xylitol production carried out using pretreated hemicellulose hydrolyzates from corncob, rice straw, and wheat straw. Experimental analysis and modeling results revealed a maximum xylitol yield when corncob was hydrolyzed with Pachysolen tannophilus.