Induction of resistance mechanisms in Rhodotorula toruloides for growth in sugarcane hydrolysate with high inhibitor content

Abstract

The oleaginous yeast Rhodotorula toruloides is a potential lipid producer for biodiesel production. However, this yeast shows growth inhibition due to harmful compounds when cultivated in hemicellulose hydrolysate. Here, we present a comparative analysis of colony selection and heterologous adaptive laboratory enhancement (ALE) strategies for obtaining robust strains. We implemented these ALE strategies for R. toruloides in a culture medium containing sugarcane hemicellulose hydrolysate. Our comparison study showed that the strain obtained with heterogeneous ALE strategy (Rth) reached a µ max of 55% higher than the parental strain. It also exhibited higher biomass production (6.51 g/l) and lipid content (60%). ALE with colony selection strategy (Rtc) had a fitness gain in terms of shortening of the lag phase (9 h) when compared to Rth and parental strain (11.67, 12.33 h, respectively). When cultivated in Eucalyptus urograndis hemicellulose hydrolysate, the Rth strain achieved a high lipid content, 64%. Kinetics studies showed a strong effect of acetic acid as a repressor of xylose consumption during R. toruloides cultivation. Key points• Distinct adaptive laboratory strategies resulted in strains with different physiologies.• Heterologous adaptive laboratory enhancement provided the best results (fitness gain of 55% in µmax).• The Rth strain achieved a lipid content of 64.3% during cultivation in eucalyptus hemicellulose hydrolysate.

Induction of Resistance of Antagonistic Bacterium Burkholderia contaminans to Postharvest Botrytis cinerea in Rosa vinifera

“…There are many factors that can induce plant resistance. As a biological inducer, antagonistic bacteria can induce the resistance of fruits and vegetables to pathogens during postharvest storage, so as to reduce decay [ 10 ]. In general, antagonistic bacteria can change the resistance of fruits and vegetables by inducing the activity of resistance-related enzymes, regulating the metabolism of reactive oxygen species, promoting plants to produce defensins, and changing cell structure.…”

Engineering transcriptional regulation of pentose metabolism in Rhodosporidium toruloides for improved conversion of xylose to bioproducts

“…The oleaginous yeast Rhodosporidium toruloides (also known as Rhodotorula toruloides ) consumes a wide range of carbon compounds derived from plant biomass, including six carbon sugars, five carbon sugars, and lignin breakdown products [ 4 ]. R. toruloides is also relatively tolerant of many biomass breakdown products that inhibit the growth of other microorganisms [ 5 ] and even more robust strains have been isolated through adaptive laboratory evolution [ 6 , 7 ]. This extensive catabolic capability plus its native biosynthetic capacity for lipids and carotenoids make it an attractive platform for bioconversion of mixed-biomass hydrolysate feedstocks [ 8 , 9 ].…”