title: Optimisation of α-terpineol production by limonene biotransformation using Penicillium digitatum DSM 62840.
abstract: BACKGROUND
  In this study, (R)-(+)-limonene biotransformation using three fungal strains was compared. Penicillium digitatum DSM 62840 was distinguished for its capacity to transform limonene into α-terpineol with high regioselectivity. Growth kinetics in submerged liquid culture and the effects of growth phase and contact time on biotransformation were studied using this strain. Substrate concentration, co-solvent selection, and cultivation conditions were subsequently optimised.
  
  
  RESULTS
  The maximum concentration of α-terpineol (833.93 mg L(-1)) was obtained when the pre-culture medium was in medium log-phase by adding 840 mg L(-1) substrate dissolved in ethanol and cultivation was performed at 24 °C, 150 rpm, and pH 6.0 for 12 h. Addition of small amounts of (R)-(+)-limonene (84 mg L(-1)) at the start of fungal log-phase growth yielded a 1.5-fold yield of α-terpineol, indicating that the enzyme was inducible.
  
  
  CONCLUSIONS
  Among these three strains tested, P. digitatum DSM 62840 was proved to be an efficient biocatalyst to transform (R)-(+)-limonene to α-terpineol. Further studies revealed that the optimal growth phase for biotransformation was in the medium log phase of this strain. The biotransformation represented a wide tolerance of temperature; α-terpineol concentration underwent no significant change at 8-32 °C. The biotransformation could also be performed using resting cells.
authors.affiliation: Key Laboratory of Environment Correlative Dietology, Ministry of Education, College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Ya-Nan
authors.initials: YN
authors.lastname: Tai
authors.affiliation: Key Laboratory of Environment Correlative Dietology, Ministry of Education, College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Min
authors.initials: M
authors.lastname: Xu
authors.affiliation: Key Laboratory of Environment Correlative Dietology, Ministry of Education, College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Jing-Nan
authors.initials: JN
authors.lastname: Ren
authors.affiliation: Key Laboratory of Environment Correlative Dietology, Ministry of Education, College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Man
authors.initials: M
authors.lastname: Dong
authors.affiliation: Key Laboratory of Environment Correlative Dietology, Ministry of Education, College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Zi-Yu
authors.initials: ZY
authors.lastname: Yang
authors.affiliation: Key Laboratory of Environment Correlative Dietology, Ministry of Education, College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Si-Yi
authors.initials: SY
authors.lastname: Pan
authors.affiliation: Key Laboratory of Environment Correlative Dietology, Ministry of Education, College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Gang
authors.initials: G
authors.lastname: Fan
mesh_terms: D001711:Biotransformation; D000081005:Cyclohexane Monoterpenes; D053138:Cyclohexenes / Q000378:metabolism*; D005503:Food Additives / Q000378:metabolism*; D006801:Humans; D000077222:Limonene; D039821:Monoterpenes / Q000378:metabolism*; D010407:Penicillium / Q000378:metabolism*; D013729:Terpenes / Q000378:metabolism*
chemical_list: D000081005:Cyclohexane Monoterpenes; D053138:Cyclohexenes; D005503:Food Additives; D039821:Monoterpenes; D013729:Terpenes; C016775:alpha-terpineol; D000077222:Limonene
keywords: (R)-(+)-limonene; Penicillium digitatum; biotransformation; monoterpene; α-terpineol