Biodegradation of crude oil by immobilized Exiguobacterium sp. AO-11 and shelf life evaluation

Abstract

Exiguobacterium sp. AO-11 was immobilized on bio-cord at 109 CFU g−1 carrier for the removal of crude oil from marine environments. To prepare a ready-to-use bioremediation product, the shelf life of the immobilized cells was calculated. Approximately 90% of 0.25% (v/v) crude oil removal was achieved within 9 days when the starved state of immobilized cells was used. The oil removal activity of the immobilized cells was maintained in the presence of oil dispersant (89%) and at pH values of 7–9. Meanwhile, pH, oil concentration and salinity affected the oil removal efficacy. The immobilized cells could be reused for at least 5 cycles. The Arrhenius equation describing the relationship between the rate of reaction and temperature was validated as a useful model of the kinetics of retention of activity by an immobilized biocatalyst. It was estimated that the immobilized cells could be stored in a non-vacuum bag containing phosphate buffer (pH 7.0) at 30 °C for 39 days to retain the cells at 107 CFU g−1 carrier and more than 50% degradation activity. These results indicated the potential of using bio-cord-immobilized crude oil-degrading Exiguobacterium sp. AO-11 as a bioremediation product in a marine environment.

Physiological changes in Rhodococcus ruber S103 immobilized on biobooms using low-cost media enhance stress tolerance and crude oil-degrading activity

“…6 c). Similarly, in a recent study, the starvation state of cells was obtained after prolonged storage, resulting in faster hydrocarbon biodegradation than with fresh cells 47 . Furthermore, the biobooms preserved in SM at RT for 100 days was still active and provided the highest crude oil biodegradation (85.2 ± 2.3%) in CFMM at 3 days (Fig.…”

“…The immobilized cells were enumerated daily for 5 days as described by Naloka et al 12 . The morphology of the immobilized cells was visualized by scanning electron microscopy (SEM) using a JSM-IT500HR model (JEOL Ltd., Tokyo, Japan) according to Sakdapetsiri et al 47 .…”

Immobilized Bacterial Cells on Electrospun Nanofibers for Crude Oil Spills Treatment and Bioremediation

“…According to the findings, it was established that aldehyde fibers have the most favorable immobilization environment for the different bacterial species as well as biodegradation of crude oil. [111] Another study was carried out by Sakdapetsiri et al [112] in which they immobilized Exiguobacterium sp on different polymeric materials that included polyurethane foam, polypropylene nanofibers, and aqua-porous gel for biodegradation of crude oil. Similarly, their findings proved the efficiency of immobilized vs un-immobilized cells in the degradation of crude oil.…”

“…Immobilized cells were able to remove nearly 90 % of the oil under study in about 9 days and also they were able to be reused up to five times without significant loss of activity. [112] Partovinia et al [113] reported immobilization of Bacillus licheniformis on polyvinyl alcohol, alginate nanofibers reinforced by halloysite nanotubes (HNTs), and cross-linked with glyoxal (GO) for bioremediation of crude oil. Biodegradation studies revealed a higher performance of immobilized bacteria on nanofiber webs (NC-NFWs) compared to the free cells (85 % and 48 % degradation respectively), as depicted in Figure 8.…”

“…Another study was carried out by Sakdapetsiri et al [112] . in which they immobilized Exiguobacterium sp on different polymeric materials that included polyurethane foam, polypropylene nanofibers, and aqua‐porous gel for biodegradation of crude oil.…”