Poly-gamma-glutamic acid-containing vaccine(BL)

This study aimed to investigate the effects of poly-ɤ-glutamic acid (PGA) addition and pH adjustment on the rheological properties of cookie dough for 3D printing. Adding 1-2% PGA to the dough increased the storage modulus (G'), loss modulus (G''), shear modulus, tan δ, yield stress (τ₀), phase angle, apparent viscosity, and hardness. Similarly, increasing the dough's pH from 6.0 to 8.5 enhanced G', G'', shear modulus, τ₀, and hardness. The addition of Alcalase to dough with high hardness modified the rheological parameters, making them to meet the required material criteria. The pH adjustment made the Alcalase treatment effective in modifying the parameters. The addition of 1% PGA or pH adjustment enabled successful 3D printing of the dough by improving fidelity, shape retention, and extrudability. Therefore, PGA addition and pH adjustment are effective methods for tailoring the physical properties of cookie dough for 3D printing applications.

To investigate the effect of poly-γ-glutamic acid (γ-PGA) biopreparation on ameliorating coastal saline soil, three treatments were established: soil salt washed treatment (CK), soil salt washed with added γ-PGA (PGA), soil salt washed with added γ-PGA biopreparation (PGAB). This study determined the effects of γ-PGA on coastal saline soil by analyzing soil aggregate, soil evaporation, soil vertical water and salt distribution, and soil cation content, soil pH, soil nutrient content and soil microorganism quantity. Results showed that γ-PGA had an ameliorative effect on saline soil, with the PGAB treatment exhibiting the most pronounced ameliorative effect compared to CK. Adding PGAB reduced soil evaporation by 30.45 %, soil salt content by 27.91 %, meanwhile increasing plant height by 33.86 %, plant fresh weight by 98.54 %, soil aggregate diameter by 6.68 times, soil water content by 26.47 % (P < 0.05). Additionally, soil total nitrogen was increased by 50.0 % in PGAB treatment, and available nitrogen and phosphorus contents were increased by 1.68 times and 85.83 % (P < 0.05), respectively. Populations of soil-culturable bacteria and fungi of PGAB treatment increased by 65.96 % and 1.23 times, respectively (P < 0.05). After salt-washing process, adding PGAB improved soil physicochemical properties, which altered the ecological environment of rhizosphere soil and promoted plant growth. The results can provide a practical approach for ameliorating coastal saline soils.