Synthesis of (-)-β-caryophyllene oxide via regio- and stereoselective endocyclic epoxidation of β-caryophyllene with Nemania aenea SF 10099-1 in a liquid-liquid interface bioreactor (L-L IBR)

Microbial transformation of water-insoluble substrates by two types of novel interface bioprocesses, tacky liquid-liquid interface bioreactor and non-aqueous sporular bioconversion system

Although microbial transformation has been expected as a substitution technology for organic synthesis, microbial toxicity and water-insolubility of synthetic substrates prevent the practical application of the technology. For these problems, the authors have developed two types of interfacial bioprocesses, solid-liquid and liquid-liquid interface bioreactors and applied the systems to many microbial transformations. In the bioreactors, addition of substrates and accumulation of products were remarkably enhanced based on the toxicity alleviation effect on the interfaces and solubilization of substrates and/or products in an organic phase of the bioreactors. Recently, a novel tacky liquid-liquid interface bioreactor has been developed and applied to actinomycetes and yeasts. Furthermore, a novel bioconversion system with fungal spores in an organic phase has been constructed based on the combination of two facts as follows: (i) the fungal spores are never resting cells and are active ones like the vegetable cells, (ii) the fungal spores have the excellent solvent-tolerance. In this review, the tacky liquid-liquid interface bioreactor (L-L IBR_tac) and the non-aqueous sporular bioconversion system with immobilized fungal spores (NASB) are mainly given outlines.

Botryane terpenoids produced by Nemania bipapillata, an endophytic fungus isolated from red alga Asparagopsis taxiformis - Falkenbergia stage

A chemical study of the EtOAc extract of Nemania bipapillata (AT-05), an endophytic fungus isolated from the marine red alga Asparagopsis taxiformis - Falkenbergia stage, led to the isolation of five new botryane sesquiterpenes, including the diastereomeric pair (+)-(2R,4S,5R,8S)-(1) and (+)-(2R,4R,5R,8S)-4-deacetyl-5-hydroxy-botryenalol (2), (+)-(2R,4S,5R,8R)-4-deacetyl-botryenalol (3), one pair of diastereomeric botryane norsesquiterpenes bearing an unprecedented degraded carbon skeleton, (+)-(2R,4R,8R)-(4) and (+)-(2R,4S,8S)-(5), which were named nemenonediol A and nemenonediol B, respectively, in addition to the known 4β-acetoxy-9β,10β,15α-trihydroxyprobotrydial (6). Their structures were elucidated using 1D and 2D NMR, HRESIMS and comparison with literature data of similar known compounds. The absolute configurations of 2, 3 and 4 were deduced by comparison of experimental and calculated electronic circular dichroism (ECD) spectra, while those of 1 and 5 were assigned from vibrational circular dichroism (VCD) data. Compound 4 weakly inhibited acetylcholinesterase, whereas compound 1 inhibited both acetylcholinesterase and butyrylcholinesterase. Compounds 1, 3, 5 and 6 were tested against two carcinoma cell lines (MCF-7 and HCT-116), but showed no significant citotoxicity at tested concentrations (IC₅₀ > 50 µM).

Production of Valuable Lipophilic Compounds by Using Three Types of Interface Bioprocesses: Solid-Liquid Interface Bioreactor, Liquid-Liquid Interface Bioreactor, and Extractive Liquid-Surface Immobilization System

Bioconversions such as enzymatic and microbial transformations are attractive alternatives to organic synthesis because of practical advantages such as resource conservation, energy efficiency, and environmentally harmonic properties. In addition, the production of secondary metabolites through microbial fermentation is also useful for manufacturing pharmaceuticals, agricultural chemicals, and aroma compounds. For microbial production of useful chemicals, the authors have developed three unique interfacial bioprocesses: a solid-liquid interface bioreactor (S/L-IBR), a liquid-liquid interface bioreactor (L/L-IBR), and an extractive liquid-surface immobilization (Ext-LSI) system. The S/L-IBR comprises a hydrophobic organic solvent (upper phase), a microbial film (middle phase), and a hydrophilic gel such as an agar plate (lower phase); the L/L-IBR and the Ext-LSI consist of a hydrophobic organic solvent (upper phase), a fungal mat with ballooned microspheres (middle phase), and a liquid medium (lower phase). All three systems have unique and practically important characteristics such as utilization of living cells, high concentration of lipophilic substrates/products in an organic phase, no requirement for aeration and agitation, efficient supply of oxygen, easy recovery of product, high regio- and stereoselectivity, and wide versatility. This paper reviews the principle, construction, characteristics, and application of these interfacial systems for producing lipophilic compounds such as useful aroma compounds, citronellol-related compounds, β-caryophyllene oxide, and 6-penty-α-pyrone.

Solvent-tolerance of fungi located on an interface between an agar plate and an organic solvent

While 6 by 20 of type culture fungi could grow on an interface between organic solvent (log P, 4.12) and agar plate, 13 by 20 of strains could form a large colony after the removal of more toxic solvent, such as styrene (log P, 2.95) and tert-butyl acetate (log P, 1.76) because of viability of spores on the interface.

Relationship between interfacial hydrophobicity and hydroxylation activity of fungal cells located on an organic-aqueous interface

In a liquid-liquid interface bioreactor, fungal cells locate in a hydrophilic polyacrylonitrile microsphere layer on an aqueous-organic interface. In this article, effects of hydrophobicity of the interface on n-decane hydroxylation activity of Monilliera sp. NAP 00702 was examined. (-)-4-Decanol production was significantly enhanced to 132% by addition of polytetrafluoroethylene.

Enhancement of 6-pentyl-α-pyrone fermentation activity in an extractive liquid-surface immobilization (Ext-LSI) system by mixing anion-exchange resin microparticles

The addition of anion-exchange resin microparticles into a polyacrylonitrile (PAN) ballooned microsphere layer drastically enhanced the fermentative activity of Trichoderma atroviride AG2755-5NM398 in an extractive liquid-surface immobilization (Ext-LSI) system. The production of 6-pentyl-α-pyrone (6PP), a fungicidal secondary metabolite, was 1.92-fold higher than the control (PAN alone).