The cell cycle and the transcriptome dynamics of yeast exposed to extracellular self-DNA during an aerobic batch culture on glucose have been investigated using cytofluorimetric and RNA-seq analyses. In parallel, the same study was conducted on yeast cells growing in the presence of (heterologous) nonself-DNA. The self-DNA treatment determined a reduction in the growth rate and a major elongation of the diauxic lag phase, as well as a significant delay in the achievement of the stationary phase. This was associated with significant changes in the cell cycle dynamics, with slower exit from the G0 phase, followed by an increased level of cell percentage in the S phase, during the cultivation. Comparatively, the exposure to heterologous DNA did not affect the growth curve and the cell cycle dynamics. The transcriptomic analysis showed that self-DNA exposure produced a generalized downregulation of transmembrane transport and an upregulation of genes associated with sulfur compounds and the pentose phosphate pathway. Instead, in the case of the nonself treatment, a clear response to nutrient deprivation was detected. Overall, the presented findings represent further insights into the complex functional mechanisms of self-DNA inhibition.

The integration of sustainable insect rearing with green downstream processing is essential for the development of circular biorefineries. This study investigated the fractionation of Tenebrio molitor biomass obtained from larvae reared on diets containing agro-industrial by-products by bench-scale supercritical CO₂ (SC-CO₂) extraction. Larvae were reared on diets containing brewer’s spent grain (BSG), cocoa bean shell (CBS), or banana peel (BP). A preliminary process screening identified 40 °C and 200 bar as the most suitable extraction conditions, providing efficient fractionation under mild operating conditions. Lipid extraction yield depended on the initial composition of the insect meals, ranging from 6.47 ± 0.26% for BSG-derived biomass to 23.02 ± 1.52% for CBS-derived biomass. SC-CO₂ extraction simultaneously produced protein-enriched meals, increasing protein content up to 69.4 ± 0.7%, with protein enrichment ranging from 14.9% to 33.4%. The recovered oils exhibited a favorable fatty acid profile, with more than 72% unsaturated fatty acids, predominantly oleic and linoleic acids. These findings show that differences in the composition of insect biomass obtained under different rearing conditions are reflected in the yield and characteristics of the fractions recovered under identical extraction conditions. Integrating rearing substrate selection with SC-CO₂ extraction represents an effective strategy to produce high-value protein-enriched meals and oils from agro-industrial by-products, supporting the development of sustainable insect biorefineries.

The growing demand for sustainable protein sources has increased interest in edible insects and their potential role within circular bioeconomy strategies. This study evaluated the suitability of brewer’s spent grain (BSG), cocoa bean shell (CBS), and banana peel (BP) as alternative substrates for Tenebrio molitor rearing and assessed the valorization of the resulting biomass through pilot-scale supercritical CO₂ extraction (CO₂-SFE). Larvae reared on BSG-based and BP-based diets achieved growth performances comparable to those obtained with a conventional wheat bran diet, whereas CBS-based diet resulted in lower weight gain and feed intake. No significant differences in feed conversion ratio were observed among diets. Substrate composition also affected biomass nutritional quality, with larvae reared on the BSG-based diet exhibiting the highest protein content (60.4%), whereas larvae reared on CBS-based diet exhibited the highest lipid content (29.3%). CO₂-SFE generated protein-enriched meals and lipid-rich extracts, yielding 12.9–15.4% oil depending on the substrate. Following extraction, protein content increased to 68.5%, 50.3%, and 60.2% in BSG-, CBS-, and BP-derived meals, respectively. The extracted oils were characterized by high levels of unsaturated fatty acids, with oleic acid (42.4–47.6%) as the predominant component. Overall, the results demonstrate that agro-industrial by-products can be effectively converted into valuable insect-derived ingredients and highlight the potential of integrating substrate selection with green extraction technologies within insect biorefinery systems.