Long-chain Aldehyde

To identify the specific aldehyde that is actually involved in the light-emitting reaction of living luminous bacteria, Shimomura et al. (1974a) extracted and purified the aldehyde from 40 g each of the bacterial cells of P. phosphoreum, Achromobacter (Vibrio or Photobacterium) fischeri, and an aldehydeless mutant of A. fischeri. The aldehyde fractions were purified, and then oxidized with Tollens reagent (silver oxide dissolved in ammonia) to convert the CHO group into the COOH group. Then the acids obtained were analyzed by mass spectrometry. The results indicated that P. phosphoreum had contained a mixture of aldehydes dodecanal (5%), tetradecanal (63%) and hexadecanal (30%), as shown in Table 2.2. Thus, tetradecanal was clearly predominant in 

phosphoreum. In the case of A. fischeri, the total amount of aldehydes was only 15% of that from P. phosphoreum, which consisted of dodecanal (36%), tetradecanal (32%) and hexadecanal (20%). The contents of aldehydes having the carbon atoms of 10, 11, 13, 15, 17 and 18 were negligibly small in both bacterial species. 

---

In addition to hexadecanal, Cormier and Strehler (1953) discovered that homologous aldehydes, such as decanal and dodecanal, were also active in stimulating bacterial luminescence. Thus, they showed that bacterial luminescence requires a saturated long-chain aldehyde, but the specific aldehyde that is actually involved in the in vivo luminescence remained unknown for the next 20 years. 

The biochemical mechanism of bacterial luminescence has been studied in detail and reviewed by several authors (Hastings and Nealson, 1977 Ziegler and Baldwin, 1981 Lee et al., 1991 Baldwin and Ziegler, 1992 Tu and Mager, 1995). Bacterial luciferase catalyzes the oxidation of a long-chain aldehyde and FMNH2 with molecular oxygen, thus the enzyme can be viewed as a mixed function oxidase. The main steps of the luciferase-catalyzed luminescence are shown in Fig. 2.1. Many details of this scheme have been experimentally confirmed. 

Reduction by sodium dithionite. A small amount of sodium dithionite, solid or in solution, is added to a luciferase solution made with 50 mM phosphate, pH 7.0, containing 50 pM FMN. The amount of dithionite used should be minimal but sufficient to remove oxygen in the solution and to fully reduce the flavin. The solution made is injected into an air-equilibrated buffer solution containing a long-chain aldehyde and luciferase to initiate the luminescence reaction. With this method, the reaction mixture will be contaminated by bisulfite and bisulfate ions derived from dithionite. 

The reported quantum yields of the long-chain aldehydes in the luminescence reaction catalyzed by P. fischeri luciferase are 0.1 for dodecanal with the standard I (Lee, 1972) 0.13 for decanal with the standard I (McCapra and Hysert, 1973) and 0.15-0.16 for decanal, dodecanal and tetradecanal with the standard III (Shimomura et al., 1972). Thus, the quantum yield of long-chain aldehydes in the bacterial bioluminescence reaction appears to be in the range of 0.10-0.16. 

In the living cells of luminous bacteria, FMNH2 is produced by the reduction of FMN with NADH catalyzed by FMN-reductase. This process is, in effect, the recycling of FMN. In the cells, a long-chain aldehyde is produced by the reduction of the corresponding long-chain acid, which is also a recycling process. 

Discovery of luciferin-luciferase reaction Benzoylation of Cypridina luciferin ATP requirement in firefly luminescence Requirement for long-chain aldehyde (luciferin) in bacterial luminescence... 

No attempt is made to provide comprehensive coverage of all the work carried out in these different media, but rather to give a flavour of the kind of systems for which the different approaches may be appropriate. In all the chapters, a more detailed discussion of the rhodium catalysed hydroformylation of 1-octene to nonanal, as a representative example of the synthesis of a long chain aldehyde with relatively low volatility, is provided [13, 14], This reaction has been chosen because ... 

Despite the very attractive properties of the rhodium-based system, no commercial plants used it because the low stability of the catalyst meant that the catalyst separation problem prevented commercialisation. Very recently, this situation has changed with the introduction of rhodium-based plant by Sasol in South Africa which uses technology developed by Kvaemer Process Technology (now Davy Process Technology). This batch continuous plant produces medium-long chain aldehydes and the separation is carriedoutbylow pressure distillation [16-18]... 

The low pressure distillation may also lead to volatilisation of the ligand so that ligand losses may be high. Some of this ligand will be recycled, whilst some must be replaced. Finally, there is a major issue concerning heavies formation in systems manufacturing long chain aldehydes. 

Saturated hydrocarbons Unsaturated hydrocarbons Wax esters Steryl esters Long chain aldehydes Triacylglycerols Long chain alcohols Free fatty acids Quinones Sterols... 

This enzyme [EC 1.2.1.48] catalyzes the reaction of a long-chain aldehyde with NAD to produce a long-chain acid anion and NADH. The best substrate is reported to be dodecylaldehyde. 

LACTATE DEHYDROGENASE LEUCINE DEHYDROGENASE LONG-CHAIN ALDEHYDE DEHYDROGENASE... 

The GC/MS analysis showed the acetone-insoluble portion to contain hydrocarbons, long-chain aldehydes and alcohols, fatty acids and fatty acid esters while the acetone soluble portion contained terpenes and terpene esters. The yields of the general chemical classes as determined in the analysis of the five samples are summarized in Table III. A high yield of long-chain alcohols (primarily 1-hexacosanol) is found in all the accessions. While the yields are generally comparable in the North American samples, a significantly... 

The groups of Burczyk, Takeda, and others have made thorough studies of cyclic acetals, such as 1,3-dioxolane (five-membered ring) and 1,3-dioxane (six-membered ring) compounds, illustrated in Fig. 13. They are typically synthesized from a long-chain aldehyde by reaction with a diol or a higher polyol. Reaction with a vicinal diol gives the dioxolane [40-42] and 1,3-diols yield dioxanes [43,44]. 

Fig.13 Preparation of 1,3-dioxolane surfactant (a) and 1,3-dioxane surfactant (b) from a long-chain aldehyde and a 1,2-and a 1,3-diol, respectively...

Protoplast fusion has also been successfiilly used to produce novel mold isoprenoids, such as citreoanthrasteroids and citreohybridones (Nakada 2000). Long chain aldehydes, valuable as a bio-flavor, have also been secured along similar procedures fiom tMli cultures of the green seaweed Ulva pertusa, regenerated fiom protoplasts (Fujimura 1990). 

Fujimura, T. Kawai, T. Shiga, M. Kajiwara, T. Hatanaka, A. (1990) Long-chain aldehyde production in thalli culture of the marine green alga Ulva pertusa. Phytochanistry, 29, 745-7. 

---