Soil salinization negatively affects plant growth and threatens food security. Halotolerant plant growth-promoting bacteria (PGPB) can alleviate salt stress in plants via diverse mechanisms. In the present study, we isolated salt-tolerant bacteria with phosphate-solubilizing abilities from the rhizosphere of Salix linearistipularis, a halophyte distributed in saline-alkali soils. Strain A103 showed high phosphate solubilization activity and was identified as Enterobacter asburiae based on genome analysis. In addition, it can produce indole-3-acetic acid (IAA), siderophores, and 1-aminocyclopropane-1-carboxylate (ACC) deaminase. Genome mining has also revealed the presence of several functional genes involved in the promotion of plant growth. Inoculation with A103 markedly improved alfalfa growth in the presence of 100 mM NaHCO3. Under alkali stress, the shoot and root dry weights after bacterial inoculation improved by 42.9 % and 21.9 %, respectively. Meanwhile, there was a 35.9-37.1 % increase in the shoot and root lengths after treatment with A103 compared to the NaHCO3-treated group. Soluble sugar content, peroxidase and catalase activities increased in A103-inoculated alfalfa under alkaline stress. A significant decrease in the malondialdehyde content was observed after treatment with strain A103. Metabolomic analysis indicated that strain A103 positively regulated alkali tolerance in alfalfa through the accumulation of metabolites, such as homocarnosine, panthenol, and sorbitol, which could reduce oxidative damage and act as osmolytes. These results suggest that halophytes are valuable resources for bioprospecting halotolerant beneficial bacteria and that the application of halotolerant growth-promoting bacteria is a natural and efficient strategy for developing sustainable agriculture.

Thin plastic films used for packing food materials are unsafe for consumers and are not readily degradable. Single-use plastic films accumulate in the environment and cause adverse effects in the food chain. In this study, Kappaphycus alvarezii, which has the value-added polymer carrageenan, was used for developing a bioplastic film along with the plasticizer polyethylene glycol (PEG 3000). Different concentrations of seaweed were used (3%, 4% and 5% dry weight), of which 4% had a higher tensile strength than the other concentrations. The physical and mechanical properties of the developed plastic films, such as thickness, tensile strength (TS), water vapor transmission rate (WVTR), oxygen transmission rate (OTR) and color, were tested for packaging applications in the food industry. A higher concentration of seaweed increased the WVTR, and a lower concentration increased the OTR. In addition, the biodegradation of the developed bioplastic was tested using isolated deep-sea microbial consortia to meet environmental standards. A deep-sea marine microbial consortium (Bacillus paralicheniformis G1, Bacillus subtilis G2, Bacillus subtilis Z1, and Enterobacter cloacae subsp. dissolvens Z2) degrades seaweed (Kappaphycus alvarezii)-derived bioplastic under buried soil conditions. The maximum degradation (88%) in the 5% (w/v) bioplastic film was observed within 10 days of incubation.