Polystyrene (PS) is a widely used petroleum-based plastic, that pollutes the environment because it is difficult to degrade. In this study, a PS degrading bacterium identified as Massilia sp. FS1903 was successfully isolated from the gut of Galleria mellonella (Lepidoptera: Pyralidae) larvae that were fed with PS foam. Scanning electron microscopy and X-ray energy dispersive spectrometry showed that the structure and morphology of the PS film was destroyed by FS 1903, and that more oxygen appeared on the degraded PS film. A water contact angle assay verified the chemical change of the PS film from initially hydrophobic to hydrophilic after degradation. X-ray photoelectron spectroscopy further demonstrated that more oxygen-containing functional groups were generated during PS degradation. After 30 days of bacterial stain incubation with 0.15 g PS, 80 ml MSM, 30°C and PS of Mn 64400 and Mw 144400 Da, the weight of the PS film significantly decreased, with 12.97 ± 1.05% weight loss. This amount of degradation exceeds or is comparable to that previously reported for other species of bacteria reported to degrade PS. These results show that Massilia sp. FS1903 can potentially be used to degrade PS waste.

In insects, odorant-binding proteins (OBPs) and chemosensory proteins (CSPs) are primary peripheral olfactory proteins playing critical roles in odorant detection. In this study, we present the first identification of OBPs and CSPs from the transcriptome of grape phylloxera Daktulosphaira vitifoliae Fitch, an important pest that damages both roots and leaves of grapes. The OBPs contained six conserved cysteine residues and the CSPs contained four conserved cysteine residues in this insect. Phylogenetic analysis showed that most of the olfactory proteins were closely related to OBPs and CSPs from other aphids. However, DviOBP7 and DviCSP9 were different because they were classified into different independent branches, respectively. Real-time polymerase chain reaction (RT-PCR) was used to examine the tissue expression of these transcripts. DviOBP1, DviOBP6, and DviOBP7 were uniquely or primarily expressed in antennae and not in the body. DviOBP2 was more abundantly expressed in the body than in the antennae. The expression levels of OBPs and CSPs of phylloxera varied depending upon where they were expressed in different body tissues.

Genipin was used as a crosslinking agent to prepare magnetic genipin-crosslinked chitosan beads, which were then used as a carrier for immobilizing recombinant cutinase from Fusarium solani (FSC) to obtain immobilized FSC. The optimal temperature for the immobilized FSC was 55 °C, which was 5 °C higher than that of the free enzyme, whereas its optimal pH was increased from 8.0 to 9.0; this indicates that the immobilized FSC had improved pH and thermal stability. After repeated use for 10 cycles, the activity of the immobilized FSC remained at more than 50%; after being stored at 4 °C for 30 days, its activity was still approximately 88%. We also found that the Km of the immobilized FSC was higher than that of the free enzyme. These results indicate that the performance of FSC was improved after immobilization, which is an important basis for the subsequent application of FSC in industrial production.