Isolation and screening of d-limonene-resistant microorganisms

Abstract

This study reports the isolation of microorganisms that are resistant to environment containing limonene, the most important residue in the citrus industry. For the isolation, samples collected from strategic places of a citrus processing plant (yellow water, entrance and exit of the bagasse tank, effluent and deteriorated fruits found in bins, machine straps, fruit washers and plant floor), some citrus fruit and mint from local market were used. The samples were incubated in rotary shaker at 30ºC/150rpm for 48h or 7 days in YM medium containing 0.1% limonene. Great part of the 112 strains recovered after 48h and the 126 strains recovered after 7 days were identified as Gram positive bacilli, followed by Gram negative bacilli, yeasts and Gram positive cocci, besides five fungi. About half of the Gram positive and Gram negative bacilli and yeasts and some Gram positive Cocci were resistant to limonene concentrations up to 2% in the medium broth. Amongst them seventy were able to grow in mineral medium containing limonene as sole carbon source. The research described in this paper is the initial step for the exploration of flavor compounds production via biotransformation of limonene, a nonexpensive by-product of citrus industry.

Optimization of R-(+)-α-terpineol production by the biotransformation of R-(+)-limonene

“…When compared to bacteria, fungi seem to be more sensitive to limonene [5], possibly because this monoterpene increases the fluidity of fungal membranes, leading to a high unspecific membrane permeability and loss of membrane integrity [28]. In this study, the limonene concentration showed a negative effect on the levels tested for 72 h (P \ 0.1) and 96 h (P \ 0.13) of biotransformation (Table 3), which might be explained by the toxic activity of R-(+)-limonene on the F. oxysporum.…”

Characterization of PLA-limonene blends for food packaging applications

“…d-limonene can be found in a variety of citrus, indeed is the main component of citrus oils and one of most important contributors to citrus flavor [10,11]. Is the most abundant monocyclic monoterpene in nature and represents more than 90% of orange peel oil, being the most important residue in the citrus industry [12]. The limonene diffusion through packaging has been widely studied in different food contact materials such as polyethylene (PE) [13], low density polyethylene (LDPE) [14], high density polyethylene (HDPE), polystyrene (PS) [15] and PLA [15,16].…”

Isolation and screening of microorganisms with potential for biotransformation of terpenic substrates

“…The medium (Bicas and Pastore, 2007) 1%, v/v). A mineral medium containing equivalent quantity of glucose in place of the terpenes was used as the control.…”

“…In biotransformation processes, the usual limonene concentration applied varies from 0.2 to 1% (Bicas and Pastore, 2007). For this reason, the maximum concentration used in the experiments was 1%.…”

“…Thus, the strains whose sporulation occurred sooner in the presence of the terpenes were considered negatively affected by the terpenes and consequently not used in further experiments. As stated by Bicas and Pastore (2007), the substrate resistance does not guarantee a high biotransformation activity, but it is an essential characteristic to a biotransforming agent. That way, this step was configured as an important part of the study.…”