Third generation biodiesel processing from microbial lipids using low-cost lignocellulosic feedstocks has attracted much attention. Endophytes isolated from oleaginous plants possibly have the capacity to accumulate lipids similar to the hosts. However, little work has been reported in terms of endophytic bacteria isolation from oleaginous plants and their lipid production using lignocellulosic hydrolysate as substrate. A new oleaginous endophyte HB1310 has been isolated from the thin-shelled walnut, and identified as Bacillus subtilis on the basis of both 16S rDNA gene sequencing and examination of its physiological and biochemical properties. This strain effectively accumulates cellular lipids using cotton stalk hydrolysate as a substrate. The optimum C/N ratio, culture temperature, and pH value were determined to be 50/1, 30°C, and 6.5, respectively. Batch fermentation was conducted in a bioreactor using these parameters. Satisfactory production, with a maximum lipid productivity of 2.3 g/L, lipid content of 39.8% (w/w), and cell dry weight (CDW) of 5.7 g/L, was obtained at a culture time of 48 h. Variations in the fluorescent intensity and lipid inclusion formation of cells collected at different sampling times illustrate the potential of this bacterium to be useful for cellular lipid production. The fatty acid profile of the produced bacterial lipids showed that the major constituents are myristic, palmitic, stearic, oleic, and linoleic acids with an estimated cetane number of about 61.8, indicating that this strain may be suitable for biodiesel production. The present investigation is the first report of an oleaginous endophytic bacterium isolated from the thin-shelled walnut. This strain is capable of producing high lipid contents rapidly using cotton stalk hydrolysate as a substrate, and its lipids are suitable for use as the feedstock for biodiesel production.

Solid state fermentation with Trametes versicolor was carried out on agricultural wastes containing bisphenol A (BPA). It was found that BPA degradation was along with the occurrence of laccase production, and wheat bran and corn straw were identified as suitable mixed substrates for laccase production. In the process of BPA degradation with T. versicolor, laccase activity increased rapidly at the 6th–10th day after inoculation. Moreover, BPA can enhance the production of laccase. After 10 days of fermentation, degradation rate of BPA exceeded 90% without the usage of mediators ABTS and acetosyringone at pH 4.0–8.0. In addition, metal ions did not affect the BPA degradation with T. versicolor. In vitro, the optimum pH range of BPA degradation with laccase was in the acidic region with the optimal performance of pH 5.0. Metal ions Cu²⁺, Zn²⁺, and Co²⁺ showed little effect on BPA degradation. However, Fe³⁺ and Fe²⁺ substantially inhibited the BPA degradation. Natural mediator acetosyringone showed optimum enhancement on BPA degradation. Greater than 90% of the estrogenic activity of BPA was removed by T. versicolor and its laccase. Compared to in vitro degradation with laccase, this study shows that the process of simultaneous laccase production and BPA degradation with T. versicolor was more advantageous since BPA can enhance the laccase production, mediators were unnecessary, degradation rate was not affected by metal ions, and the applicable pH range was broader. This study concludes that T. versicolor and laccase have great potential to treat industrial wastewater containing BPA.