Isoprene is a climate-active biogenic volatile organic compound (BVOC), emitted into the atmosphere in abundance, mainly from terrestrial plants. Soil is an important sink for isoprene due to its consumption by microbes. In this study, we report the ability of a soil bacterium to degrade isoprene. Strain 13f was isolated from soil beneath wild Himalayan cherry trees in a tropical restored forest. Based on phylogenomic analysis and an Average Nucleotide Identity score of >95%, it most probably belongs to the species Alcaligenes faecalis. Isoprene degradation by Alcaligenes sp. strain 13f was measured by using gas chromatography. When isoprene was supplied as the sole carbon and energy source at the concentration of 7.2 × 105 ppbv and 7.2 × 106 ppbv, 32.6% and 19.6% of isoprene was consumed after 18 days, respectively. Genome analysis of Alcaligenes sp. strain 13f revealed that the genes that are typically found as part of the isoprene monooxygenase gene cluster in other isoprene-degrading bacteria were absent. This discovery suggests that there may be alternative pathways for isoprene metabolism.

Kombucha is a fermented tea beverage obtained by the symbiosis of yeast, acetic acid bacteria and some lactic acid bacteria, and it has many health benefits. The aim of this study was to investigate the potential of adding Indian gooseberry as a substrate to enhance the chemical properties of kombucha. In this study, traditional kombucha made from green tea was compared to kombucha made from green tea blended with various forms of Indian gooseberry, including whole fruit, dried fruit and juice. The fermentation was performed for 21 days and samples were collected every 3 days to enumerate the total number of yeast and bacteria. Physical and chemical properties, including total soluble solids, alcohol content, pH, acetic acid content, total phenolic and flavonoid content, antioxidant activity and organic acids, were analyzed. The results revealed that the dried Indian gooseberry kombucha (DIGK) demonstrated significantly high total phenolic content and total flavonoid content. In addition, DIGK had the highest D-Saccharic acid-1,4 lactone (DSL) on the 9th day of fermentation. This discovery suggests that dried Indian gooseberry can be used as an alternative substrate for kombucha fermentation to create a new type of kombucha beverage with enhanced chemical properties.

Isoprene, a volatile hydrocarbon emitted largely by plants, plays an important role in regulating the climate in diverse ways, such as reacting with free radicals in the atmosphere to produce greenhouse gases and pollutants. Isoprene is both deposited and formed in soil, where it can be consumed by some soil microbes, although much remains to be understood about isoprene consumption in tropical soils. In this study, isoprene-degrading bacteria from soils associated with tropical plants were investigated by cultivation and cultivation-independent approaches. Soil samples were taken from beneath selected framework forest trees and economic crops at different seasons, and isoprene degradation in soil microcosms was measured after 96 h of incubation. Isoprene losses were 4–31% and 15–52% in soils subjected to a lower (7.2 × 105 ppbv) and a higher (7.2 × 106 ppbv) concentration of isoprene, respectively. Sequencing of 16S rRNA genes revealed that bacterial communities in soil varied significantly across plant categories (framework trees versus economic crops) and the presence of isoprene, but not with isoprene concentration or season. Eight isoprene-degrading bacterial strains were isolated from the soils and, among these, four belong to the genera Ochrobactrum, Friedmanniella, Isoptericola and Cellulosimicrobium, which have not been previously shown to degrade isoprene.