Bioconversion of Pinoresinol Diglucoside and Pinoresinol from Substrates in the Phenylpropanoid Pathway by Resting Cells of Phomopsis sp.XP-8

Abstract

Pinoresinol diglucoside (PDG) and pinoresinol (Pin) are normally produced by plant cells via the phenylpropanoid pathway. This study reveals the existence of a related pathway in Phomopsis sp. XP-8, a PDG-producing fungal strain isolated from the bark of the Tu-chung tree (Eucommiaulmoides Oliv.). After addition of 0.15 g/L glucose to Phomopsis sp. XP-8, PDG and Pin formed when phenylalanine, tyrosine, leucine, cinnamic acid, and p-coumaric acid were used as the substrates respectively. No PDG formed in the absence of glucose, but Pin was detected after addition of all these substrates except leucine. In all systems in the presence of glucose, production of PDG and/or Pin and the accumulation of phenylalanine, cinnamic acid, or p-coumaric acid correlated directly with added substrate in a time- and substrate concentration- dependent manner. After analysis of products produced after addition of each substrate, the mass flow sequence for PDG and Pin biosynthesis was defined as: glucose to phenylalanine, phenylalanine to cinnamic acid, then to p-coumaric acid, and finally to Pin or PDG. During the bioconversion, the activities of four key enzymes in the phenylpropanoid pathway were also determined and correlated with accumulation of their corresponding products. PDG production by Phomopsis sp. exhibits greater efficiency and cost effectiveness than the currently-used plant-based system and will pave the way for large scale production of PDG and/or Pin for medical applications.

Strategies to enhance the production of pinoresinol and its glucosides by endophytic fungus (Phomopsis sp. XP-8) isolated from Tu-chung bark

“…The seed cultures of Phomopsis sp. XP-8 were prepared in a liquid potato dextrose medium (PDB) by cultivating 5 colonies (5 mm in diameter) formed in a 5-day potato dextrose agar (PDA) culture for 3 days at 28 °C and 180 rpm (Zhang et al 2016b ). Alternaria sp.…”

“…Previously developed liquid fermentation and the bioconversion system with Phomopsis sp. XP-8 resting cells was used (Zhang et al 2015 , 2016b ). The expression of the key genes (4-coumarate: CoA ligase, 4CL; chalcone synthase, CHS; UDP-glucosyl transferase, GT) related to the biosynthesis of Pin, PMG, and PDG was determined, and the yield of these compounds was monitored accordingly.…”

Verification of the phenylpropanoid pinoresinol biosynthetic pathway and its glycosides in Phomopsis sp. XP-8 using 13C stable isotope labeling and liquid chromatography coupled with time-of-flight mass spectrometry

“…Phe, cinnamic acid, and p -coumaric acid have been detected as products of the bioconversion (14,15). Precursor feeding and enzymatic activity measurements indicate that this strain synthesizes PDG via many steps, such as during mass flow of the phenylpropanoid pathway (16). Genomic annotation indicates that the phenylpropane pathway exists in this strain (17) and some other microorganisms (18).…”

Comparison of pinoresinol diglucoside production byPhomopsissp. XP-8 in different media and the characterisation and product profiles of the cultivation in mung bean

“…Previous studies provided evidence of the phenylalanine pathway in Phomopsis sp. XP‐8 during the PDG bioconversion . The PDG biosynthetic pathway in Phomopsis sp.…”

“…XP-8 during the PDG bioconversion. 16 The PDG biosynthetic pathway in Phomopsis sp. XP-8 may be similar to its host plants, and natural materials containing the compounds in the biosynthetic pathway might promote PDG production.…”