Lactiplantibacillus species have been historically used for food applications. Although several species are regarded as safe according to their regulatory status, the safety issues and functional roles of these lactic acid bacteria have been given attention. A selected Lactiplantibacillus strain TBRC 20328, with probiotic properties isolated from fermented Isan-style pork sausage (Mam), was evaluated for its safety through whole-genome sequencing and analysis using integrative bioinformatics tools. The metabolic genes were assessed through comparative genome analysis among Lactiplantibacillus species. The genome of the strain TBRC 20328 consisted of one circular chromosome (3.49 Mb) and five plasmids (totaling 0.25 Mb), encoding 3056 and 284 protein-coding genes, respectively. It exhibited an average nucleotide identity (ANI) with other Lactiplantibacillus pentosus strains of over 95%. Whole-genome analysis confirmed the absence of virulence and antimicrobial resistance genes, supporting its safety for food applications. Functional annotation revealed clusters for bacteriocins (plantaricin EF and pediocin) and polyketides, indicating potential roles in biopreservation and host interactions. Genes involved in the biosynthesis of some short-chain fatty acids and exopolysaccharides were also identified. Comparative genomic analysis across 33 other Lactiplantibacillus strains identified 2380 orthogroups, with 94 unique to the Lp. pentosus group. These included gene clusters involved in malonate decarboxylation, leucine biosynthesis, and 5-oxoprolinase activity. Such distinct genomic features emphasize the sustainable biotechnological potential and safety of Lp. pentosus TBRC 23028. Together, the findings highlight its promise as a safe and functional probiotic candidate with broad applications in functional food development and precision fermentation technologies.

Acid- and heat-tolerant industrial microbial strains are crucial for biotechnological production because they minimize the risk of microbial contamination and reduce energy consumption associated with cooling requirements. Here, adaptive laboratory evolution (ALE) of Aurantiochytrium limacinum was performed to improve the capability of the strain to produce docosahexaenoic acid (DHA) under acidic and high-temperature conditions. A stepwise increase from 30 to 38 °C was applied during cultivation at pH 4.5. After 30 cycles of high-temperature exposure (34 °C), an adaptive strain (BBF002) was obtained. Cell growth and DHA production of BBF002 were higher than those of the parental strain (BBF001) by 32.95 and 7.12%, respectively, at pH 4.5 and 30 °C. Based on the experimental data obtained using glucose as a carbon source, a kinetic model was developed to describe cell growth, biomass maintenance, and DHA, and we used other metabolite methods to produce the native, parental, and adaptive strains. The growth traits of the three strains could be adequately described through logistic modeling. DHA was found to be a mixed-growth product produced during exponential and stationary phases, according to the Luedeking–Piret equation.

Thraustochytrids are promising alternatives for the production of docosahexaenoic acid (DHA; C22:6 n-3), a long-chain polyunsaturated fatty acid with health benefits. For practical application of this oleaginous microorganism, an efficient cultivation method to enhance DHA production is required, which relies on several factors that support cell growth, lipid accumulation, and lipid turnover. In this study, the robust submerged fermentation of an acid- and high-temperature-tolerant strain of Aurantiochytrium limacinum was investigated. Under controlled temperature and acidic conditions (pH 4.5 and 30 °C), glucose and peptone were the best carbon and nitrogen sources for enhancing biomass and DHA production, respectively, with a glucose concentration of 60 g/L and a C/N ratio of 24 being optimal for DHA production. Applying an aeration rate of 2 vvm and an agitation speed of 300 rpm using a combination of a ring sparger and pitch-blade impeller in a stirred-tank bioreactor improved DHA production using intermittent fed-batch fermentation. The highest DHA titer was obtained at 3.01 g/L, and the DHA content in biomass was 10.69% (w/w) after intermittent feeding of cassava starch hydrolysate as the substrate.