Advanced strategy to produce insecticidal destruxins from lignocellulosic biomass Miscanthus.

BACKGROUND: Biorefineries are widely recognized as the most feasible solution to the problem of achieving environmental sustainability along with economic growth. Furthermore, pine wilt disease has caused severe environmental and economic damage worldwide to date. Herein, a highly efficient, advanced process for producing destruxins (DTXs) from Miscanthus (MCT) is reported, along with an application strategy. RESULTS: The acetic acid-sodium chlorite pretreatment of MCT (AASC-MCT) is found to improve the monosaccharide production. Through biocatalytic conversion processes (simultaneous saccharification and cultivation), Metarhizium anisopliae JEF-279 can efficiently produce DTXs from 1% (w/v) AASC-MCT, i.e., DTX E (334.8 mg/L), A (288.8 mg/L), and B (48.6 mg/L). Monochamus alternatus (MA, Japanese pine sawyer) is known to act as a mediator transferring Bursaphelenchus xylophilus to pinewood. As B. xylophilus is associated with the occurrence of pine wilt disease, biological control of MA is a major strategy or controlling this disease. In this study, upon the application of a mixture of DTXs and protease-containing culture filtrate (PCF), complete mortality of MA is observed after a 5-day incubation. The MA immune system response is believed to cause an overexpression of actin and tropomyosin as a defense mechanism against the flaccid paralysis induced by the DTXs and PCF treatment. CONCLUSIONS: These results suggest that MCT can be used as a major feedstock in the biorefinery industry and that DTXs can be applied as an insecticide for biological control of pine wilt disease via MA termination.

Combined Treatment of High Hydrostatic Pressure and Cationic Surfactant Washing to Inactivate Listeria monocytogenes on Fresh-Cut Broccoli.

This study was conducted to examine the inactivation effect of the combined treatment of high hydrostatic pressure (HHP; 400 MPa for 1, 3, and 5 min) and cationic surfactant washing (0.05% benzethonium chloride, BEC) against Listeria monocytogenes inoculated on fresh-cut broccoli (FCB). Washing with BEC at concentrations exceeding 0.05% resulted in 2.3 logreduction of L. monocytogenes counts on FCB, whereas HHP treatment had approximately 5.5- 5.6 log-reductions regardless of the treatment time. Scanning electron microscopy corroborated microbial enumeration, revealing that the combined treatment was more effective in removing L. monocytogenes from FCB than individual treatment with HHP or BEC. Color and total glucosinolate content were maintained after the combined treatment, although the hardness of the FCB slightly decreased. The results clearly suggest that the combined treatment of HHP and BEC washing has potential value as a new sanitization method to improve the microbial safety of FCB.

Biorefining Process of Carbohydrate Feedstock (Agricultural Onion Waste) to Acetic Acid.

The biorefining of agricultural waste into green chemicals has clear potential for improving global environmental sustainability. In this study, we evaluated the potential of acetic acid production from carbohydrate feedstock (onion waste, OW) as a more environmentally friendly source than feedstock produced from natural gas. In particular, OW is an ideal feedstock for the biorefining process as it contains a sufficient amount of carbohydrates (69.7%). Five days of the simultaneous saccharification and two-step fermentation (SSTF) process produced acetic acid from OW more efficiently than the simultaneous saccharification and cofermentation (SSCF) process. SSTF produced 19.3 g/L acetic acid and recorded the highest conversion yield (90.5%) from OW (6% substrate loading, w/v). These results suggested that acetic acid can be efficiently and sustainably produced from OW by the SSTF process.

Effective approach to organic acid production from agricultural kimchi cabbage waste and its potential application.

The biotransformation of agricultural waste into valuable chemicals represents a promising approach in the field of biorefining. Herein, a general but highly efficient and robust process is reported for the production of organic acid from kimchi cabbage waste using lactic acid bacteria. The organic acid produced was tested for efficacy as a biological control agent. Lactobacillus sakei WiKim31 and L. curvatus WiKim38 could efficiently produce organic acids including lactic acid (12.1 and 12.7 g/L), fumaric acid (7.4 and 7.1 g/L), and acetic acid (4.5 and 4.6 g/L) from kimchi cabbage waste (3% substrate loading, w/v) by simultaneous saccharification and fermentation processes for 48 h, and the culture filtrate induced complete mortality of J2s Meloidogyne incognita at 2.5% concentration. These results suggested that lactic acid bacteria L. sakei WiKim31 and L. curvatus WiKim38 can efficiently produce organic acids, and the culture filtrate can be applied as a microbial nematicide.

Process development of oxalic acid production in submerged culture of Aspergillus niger F22 and its biocontrol efficacy against the root-knot nematode Meloidogyne incognita.

Oxalic acid has potent nematicidal activity against the root-knot nematode Meloidogyne incognita. In this study, fermentation parameters for oxalic acid production in submerged culture of Aspergillus niger F22 at 23, 25, and 30 °C were optimized in 5-L jar fermenters. The viscosity of the culture broth increased with increasing temperature. There was a negative correlation between oxalic acid production and the apparent viscosity; high volumetric productivity of oxalic acid was obtained at low apparent viscosity (less than 1000 cP), with a productivity of more than 100 mg/L h. When the apparent viscosity was over 2500 cP, the volumetric productivity decreased below 50 mg/L h. In addition, the volumetric mass transfer coefficient, K L a, positively correlated with volumetric productivity. When the K L a value increased from 0.0 to 0.017 /s, the volumetric productivity proportionally increased up to 176 mg/L h. When the temperature decreased, K L a increased due to the decrease in viscosity, leading to increased volumetric productivity. The highest productivity of 7453.3 mg/L was obtained at the lowest temperature, i.e., 23 °C. The nematicidal activity of culture filtrate was proportional to the content of oxalic acid. Based on a constant impeller tip speed, oxalic acid production was successfully scaled up to a 500-L pilot vessel, producing a final concentration comparable to that in the 5-L jar.

Effects of 27.12 MHz Radio Frequency on the Rapid and Uniform Tempering of Cylindrical Frozen Pork Loin (Longissimus thoracis et lumborum).

Quality characteristics of frozen cylindrical pork loin were evaluated following different tempering methods: 27.12 MHz curved-electrode radio frequency (RF) at 1000 and 1500 W, and forced-air convection (FC) or water immersion (WI) at 4°C and 20°C. The developed RF tempering system with the newly designed curved-electrode achieved relatively uniform tempering compared to a parallel-plate RF system. FC tempering at 4°C was the most time-consuming process, whereas 1500 W RF was the shortest. Pork sample drip loss, water holding capacity, color, and microbiological quality declined after WI tempering at 20°C. Conversely, RF tempering yielded minimal sample changes in drip loss, microstructure, color, and total aerobic bacteria counts, along with relatively uniform internal sample temperature distributions compared to those of the other tempering treatments. These results indicate that curved-electrode RF tempering could be used to provide rapid defrosting with minimal quality deterioration of cylindrical frozen meat block products.

Effect of tempering methods on quality changes of pork loin frozen by cryogenic immersion.

The quality characteristics of pork loin frozen by cryogenic immersion were examined, such as the drip loss, cooking loss, water holding capacity, moisture content, protein solubility, lipid and protein oxidation, color, and microstructure, and compared after different tempering methods: radio frequency (27.12MHz), water immersion, forced-air convection, and microwave tempering. Forced-air tempering was the most time-consuming process, whereas electromagnetic energy methods (radio frequency and microwave) were the shortest. The tempering rate of radio frequency at 400W was 5 and 94 times greater than that obtained with water immersion and forced-air tempering, respectively. The drip loss, water holding capacity, moisture content, color, and microstructure of pork samples all declined as a result of microwave tempering. By contrast, the least degree of changes in the drip loss, microstructure, and color of the pork loin samples was obtained with radio frequency tempering, suggesting its potential application in providing rapid defrosting without quality deterioration in the frozen meat industry.