title: Influence of rice straw polyphenols on cellulase production by Trichoderma reesei.
abstract: In this study, we found that during cellulase production by Trichoderma reesei large amounts of polyphenols were released from rice straw when the latter was used as the carbon source. We identified and quantified the phenolic compounds in rice straw and investigated the effects of the phenolic compounds on cellulase production by T. reesei. The phenolic compounds of rice straw mainly consisted of phenolic acids and tannins. Coumaric acid (CA) and ferulic acid (FA) were the predominant phenolic acids, which inhibited cellulase production by T. reesei. When the concentrations of CA and FA in the broth increased to 0.06 g/L, cellulase activity decreased by 23% compared with that in the control culture. Even though the rice straw had a lower tannin than phenolic acid content, the tannins had a greater inhibitory effect than the phenolic acids on cellulase production by T. reesei. Tannin concentrations greater than 0.3 g/L completely inhibited cellulase production. Thus, phenolic compounds, especially tannins are the major inhibitors of cellulase production by T. reesei. Therefore, we studied the effects of pretreatments on the release of phenolic compounds. Ball milling played an important role in the release of FA and CA, and hot water extraction was highly efficient in removing tannins. By combining ball milling with extraction by water, the 2-fold higher cellulase activity than in the control culture was obtained.
authors.affiliation: Shanghai Key Laboratory of Bio-energy Crops, School of Life Sciences, Shanghai University, 99 Shangda Road, Shanghai 200444, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Zheng
authors.affiliation: Shanghai Key Laboratory of Bio-energy Crops, School of Life Sciences, Shanghai University, 99 Shangda Road, Shanghai 200444, China.
authors.forename: Qin
authors.initials: Q
authors.lastname: Zheng
authors.affiliation: Shanghai Key Laboratory of Bio-energy Crops, School of Life Sciences, Shanghai University, 99 Shangda Road, Shanghai 200444, China.
authors.forename: Yiyun
authors.initials: Y
authors.lastname: Xue
authors.affiliation: Shanghai Key Laboratory of Bio-energy Crops, School of Life Sciences, Shanghai University, 99 Shangda Road, Shanghai 200444, China.
authors.forename: Jiajun
authors.initials: J
authors.lastname: Hu
authors.affiliation: Shanghai Key Laboratory of Bio-energy Crops, School of Life Sciences, Shanghai University, 99 Shangda Road, Shanghai 200444, China; Energy Research Institute of Shandong Academy of Sciences, Jinan 250014, China. Electronic address: mtgao@shu.edu.cn.
authors.forename: Min-Tian
authors.initials: MT
authors.lastname: Gao
mesh_terms: D002480:Cellulase / Q000096:biosynthesis*; D004305:Dose-Response Relationship, Drug; D012275:Oryza / Q000737:chemistry*; D059808:Polyphenols / Q000494:pharmacology*; D014242:Trichoderma / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism*
chemical_list: D059808:Polyphenols; D002480:Cellulase
keywords: Cellulase; Phenolic acid; Phenolic compounds; Rice straw; Tannin; Trichoderma reesei