Cleanup of trimethylamine (fishy odor) from contaminated air by various species of Sansevieria spp. and their leaf materials.

Removal of trimethylamine (TMA) by 10 different living Sansevieria spp. and their dried leaf materials was studied. The results showed that living Sansevieria kirkii was the most effective plant while Sansevieria masoniana was the least effective in TMA removal. Two major pathways were involved in stomata opening and epicuticular wax on the leaf surface. In the presence of TMA, the stomata opening in Sansevieria spp. was induced, which enhanced TMA removal under light conditions. Dried leaf powders of Sansevieria spp. adsorbed TMA through their waxes. Therefore, both living and non-living Sansevieria spp. can be effectively used for removal of TMA.

Trimethylamine removal by plant capsule of Sansevieria kirkii in combination with Bacillus cereus EN1.

Trimethylamine (TMA) contamination produces a strong "fishy" odor and can cause pathological changes in humans. By screening native microorganisms from Sansevieria kirkii exposed to 100 ppm TMA, it was shown that endophytic bacteria number 1 (EN1) and number 2 (EN2) have a higher TMA tolerance and removal capacity than other bacteria species in a closed system. In addition, EN1 and EN2 demonstrated the ability to produce high quantities of indole-3-acetic acid (IAA) and use 1-aminocyclopropane-1-carboxylic acid (ACC), which is found normally in plant growth-promoting bacteria (PGPB). Moreover, 16S ribosomal DNA (rDNA) sequences of EN1 and EN2 identification showed that EN1 and EN2 was the same bacteria species, Bacillus cereus. B. cereus EN1 was chosen to apply with S. kirkii to remove TMA in a plant capsule, which was compared to control conditions. It was found that 500 g of soil with S. kirkii inoculated with B. cereus EN1 had a higher TMA removal efficiency than other conditions. Moreover, the flow rate of TMA-contaminated gas was varied (0.03-1 L min-1) to calculate the loading rate and elimination capacity. The maximum loading rate of 500 g soil with B. cereus EN1-inoculated S. kirkii was 2500 mg m-3 h-1, while other conditions showed only around 250-750 mg m-3 h-1. Therefore, a plant capsule with B. cereus EN1-inoculated S. kirkii had the potential to be applied in TMA-contaminated air.

Trimethylamine (fishy odor) adsorption by biomaterials: effect of fatty acids, alkanes, and aromatic compounds in waxes.

Thirteen plant leaf materials were selected to be applied as dried biomaterial adsorbents for polar gaseous trimethylamine (TMA) adsorption. Biomaterial adsorbents were efficient in adsorbing gaseous TMA up to 100% of total TMA (100 ppm) within 24 h. Sansevieria trifasciata is the most effective plant leaf material while Plerocarpus indicus was the least effective in TMA adsorption. Activated carbon (AC) was found to be lower potential adsorbent to adsorb TMA when compared to biomaterial adsorbents. As adsorption data, the Langmuir isotherm supported that the gaseous TMA adsorbed monolayer on the adsorbent surface and was followed pseudo-second order kinetic model. Wax extracted from plant leaf could also adsorb gaseous TMA up to 69% of total TMA within 24 h. Another 27-63% of TMA was adsorbed by cellulose and lignin that naturally occur in high amounts in plant leaf. Subsequently, the composition appearing in biomaterial wax showed a large quantity of short-chain fatty acids (≤C18) especially octadecanoic acid (C18), and short-chain alkanes (C12-C18) as well as total aromatic components dominated in the wax, which affected TMA adsorption. Hence, it has been demonstrated that plant biomaterial is a superior biosorbent for TMA removal.

Removal of trimethylamine (fishy odor) by C3 and CAM plants.

From screening 23 plant species, it was found that Pterocarpus indicus (C3) and Sansevieria trifasciata (crassulacean acid metabolism (CAM)) were the most effective in polar gaseous trimethylamine (TMA) uptake, reaching up to 90% uptake of initial TMA (100 ppm) within 8 h, and could remove TMA at cycles 1-4 without affecting photosystem II (PSII) photochemistry. Up to 55 and 45% of TMA was taken up by S. trifasciata stomata and leaf epicuticular wax, respectively. During cycles 1-4, interestingly, S. trifasciata changed its stomata apertures, which was directly induced by gaseous TMA and light treatments. In contrast, for P. indicus the leaf epicuticular wax and stem were the major pathways of TMA removal, followed by stomata; these pathways accounted for 46, 46, and 8%, respectively, of TMA removal percentages. Fatty acids, particularly tetradecanoic (C14) acid and octadecanoic (C18) acid, were found to be the main cuticular wax components in both plants, and were associated with TMA removal ability. Moreover, the plants could degrade TMA via multiple metabolic pathways associated with carbon/nitrogen interactions. In CAM plants, one of the crucial pathways enabled 78% of TMA to be transformed directly to dimethylamine (DMA) and methylamine (MA), which differed from C3 plant pathways. Various metabolites were also produced for further detoxification and mineralization so that TMA was completely degraded by plants.

Factors affecting xylene-contaminated air removal by the ornamental plant Zamioculcas zamiifolia.

Fifteen plant species-Alternanthera bettzickiana, Drimiopsis botryoides, Aloe vera, Chlorophytum comosum, Aglaonema commutatum, Cordyline fruticosa, Philodendron martianum, Sansevieria hyacinthoides, Aglaonema rotundum, Fittonia albivenis, Muehlenbeckia platyclada, Tradescantia spathacea, Guzmania lingulata, Zamioculcas zamiifolia, and Cyperus alternifolius-were evaluated for the removal efficiency of xylene from contaminated air. Among the test plants, Z. zamiifolia showed the highest xylene removal efficiency. Xylene was toxic to Z. zamiifolia with an LC50 of 3,464 ppm. Higher concentrations of xylene exhibited damage symptoms, including leaf tips turning yellow, holonecrosis, and hydrosis. TEM images showed that a low concentration of xylene vapors caused minor changes in the chloroplast, while a high concentration caused swollen chloroplasts and damage. The effect of photosynthetic types on xylene removal efficiency suggests that a mixture of Z. zamiifolia, S. hyacinthoides, and A. commutatum which represent facultative CAM, CAM, and C3 plants, is the most suitable system for xylene removal. Therefore, for maximum improvement in removing xylene volatile compounds under various conditions, multiple species are needed. The effect of a plant's total leaf area on xylene removal indicates that at lower concentrations of xylene, a small leaf area might be as efficient as a large leaf area.