A lipase from Lacticaseibacillus rhamnosus IDCC 3201 with thermostability and pH resistance for use as a detergent additive.

Lipases are important biocatalysts and ubiquitous in plants, animals, and microorganisms. The high growth rates of microorganisms with low production costs have enabled the wide application of microbial lipases in detergent, food, and cosmetic industries. Herein, a novel lipase from Lacticaseibacillus rhamnosus IDCC 3201 (Lac-Rh) was isolated and its activity analyzed under a range of reaction conditions to evaluate its potential industrial application. The isolated Lac-Rh showed a molecular weight of 24 kDa and a maximum activity of 3438.5 ± 1.8 U/mg protein at 60 °C and pH 8. Additionally, Lac-Rh retained activity in alkaline conditions and in 10% v/v concentrations of organic solvents, including glycerol and acetone. Interestingly, after pre-incubation in the presence of multiple commercial detergents, Lac-Rh maintained over 80% of its activity and the stains from cotton were successfully removed under a simulated laundry  setting. Overall, the purified lipase from L. rhamnosus IDCC 3201 has potential for use as a detergent in industrial applications. KEY POINTS: • A novel lipase (Lac-Rh) was isolated from Lacticaseibacillus rhamnosus IDCC 3201 • Purified Lac-Rh exhibited its highest activity at a temperature of 60 °C and a pH of 8, respectively • Lac-Rh remains stable in commercial laundry detergent and enhances washing performance.

Development of a pH indicator for monitoring the freshness of minced pork using a cellulose nanofiber.

A cellulose nanofiber (CNF)-based pH-sensitive indicator was developed by mixing CNF with red radish color extract (RRCE) to analyze the freshness of minced pork. Among various mixing conditions of RRCE solutions (0.4-1.6%) and CNF (0.5-1.25%), 0.8% RRCE/1% CNF showing higher mechanical properties, lower response to water, lower leakage of RRCE, and higher sensitivity to ammonia was selected as optimum. Ultraviolet-visible light transmittance and structural properties of the film indicated successful incorporation of RRCE into CNF, with rapid response to changes in pH caused by ammonia solution. The water vapor permeability of the indicator was maintained for 48 h. The fabricated pH-sensitive indicator showed apparent color changes from red color (fresh) to purple color (spoiled) during pork storage at refrigeration temperature. In addition, the deterioration degree was compared by measuring pH, microbial counts, and total volatile base-nitrogen level, confirming the applicability of this CNF-based film as a pH indicator.

Preparation of cellulose microfibril (CMF) from Gelidium amansii and feasibility of CMF as a cosmetic ingredient.

Cellulose microfibrils (CMF) were successfully isolated from the red alga, Gelidium amansii. G. amansii was processed in two stages, microwave digestion and high-speed blending to remove agar and extract microfibrils, respectively. After pretreatment at 180 °C for 10 min, G. amansii containing 40.1 % glucan was microfibrillated through homogenization. Morphological analysis by SEM and FTIR, and analysis of the degree of fibrillation with water retention, sedimentation, and CtCBD3 protein binding of G. amansii-derived CMF were investigated. Functional analysis of CMF showed suppression of cyclooxygenase-2 expression in both in vitro and in vivo experiments. Additionally, suppression was evident in the: i) epidermal thickness of mice skin; ii) presence of proinflammatory cytokines; and iii) inhibition of JNK1/2 and p38 phosphorylation in human keratinocyte HaCaT cells. Such activity demonstrates its anti-inflammatory properties. The results in this study showed the possibility of using CMF derived from a red alga as an anti-inflammation material.

Lactic Acid Production from a Whole Slurry of Acid-Pretreated Spent Coffee Grounds by Engineered Saccharomyces cerevisiae.

Spent coffee grounds (SCG) generated after coffee extraction are the main byproduct of the coffee industry. Valorization of the SCG has been increasingly focused following considerable attention in coffee consumption. Lactic acid bacteria fermentation is the primary source of generation of lactic acid, a monomer of polylactic acid that has various industrial applications; however, because of the low tolerance of lactic acid bacteria to toxic compounds, it is necessary to apply Saccharomyces cerevisiae to produce lactic acid whose tolerance to toxic compounds is higher. In this study, we evaluated the feasibility of using SCG as substrate for the production of lactic acid by S. cerevisiae strain expressing heterologous lactate dehydrogenase. The fermentation profiles of the engineered yeast showed that lactic acid production was promoted by xylose addition. From simultaneous saccharification and fermentation (SSF) using a whole slurry of acid-pretreated SCG, containing high amounts of hemicellulose fractions, lactic acid (0.11 g) and ethanol (0.10 g) per g SCG were obtained after 24 h of SSF, of which yields were 413% and 221% higher, respectively, than those of washed pretreated SCG. Thus, fermentation of whole slurry SCG by engineered S. cerevisiae is a suitable way of lactic acid production, selectively.

Oxidative Dimerization of PHD2 is Responsible for its Inactivation and Contributes to Metabolic Reprogramming via HIF-1α Activation.

Prolyl hydroxylase domain protein 2 (PHD2) belongs to an evolutionarily conserved superfamily of 2-oxoglutarate and Fe(II)-dependent dioxygenases that mediates homeostatic responses to oxygen deprivation by mediating hypoxia-inducible factor-1α (HIF-1α) hydroxylation and degradation. Although oxidative stress contributes to the inactivation of PHD2, the precise molecular mechanism of PHD2 inactivation independent of the levels of co-factors is not understood. Here, we identified disulfide bond-mediated PHD2 homo-dimer formation in response to oxidative stress caused by oxidizing agents and oncogenic H-ras(V12) signalling. Cysteine residues in the double-stranded ß-helix fold that constitutes the catalytic site of PHD isoforms appeared responsible for the oxidative dimerization. Furthermore, we demonstrated that disulfide bond-mediated PHD2 dimerization is associated with the stabilization and activation of HIF-1α under oxidative stress. Oncogenic H-ras(V12) signalling facilitates the accumulation of HIF-1α in the nucleus and promotes aerobic glycolysis and lactate production. Moreover, oncogenic H-ras(V12) does not trigger aerobic glycolysis in antioxidant-treated or PHD2 knocked-down cells, suggesting the participation of the ROS-mediated PHD2 inactivation in the oncogenic H-ras(V12)-mediated metabolic reprogramming. We provide here a better understanding of the mechanism by which disulfide bond-mediated PHD2 dimerization and inactivation result in the activation of HIF-1α and aerobic glycolysis in response to oxidative stress.

Semi-Empirical Structure Determination of Escherichia coli Hsp33 and Identification of Dynamic Regulatory Elements for the Activation Process.

The activation process of the redox-regulated chaperone heat shock protein 33 (Hsp33) is constituted by the oxidation-induced unfolding of the C-terminal zinc-binding domain and concomitant oligomerization of the N-terminal core domain. Herein, the semi-empirical solution structure of Escherichia coli Hsp33 in the reduced, inactive form was generated through conformational space annealing calculations, utilizing minimalistic NMR data and multiple homology restraints. The various conformations of oxidized Hsp33 and some mutant forms were also investigated in solution. Interestingly, a specific region concentrated around the interdomain linker stretch and its interacting counterparts, the N-terminal ß-strand 1 and α-helix 1, hardly showed up as signals in the NMR measurements. The NMR spectra of an Hsp33 derivative with a six-residue deletion in the disordered N-terminus implied a plausible conformational exchange associated with the identified region, and the corresponding exchange rate appeared slower than that of the wild type. Subsequent mutations that destroyed the structure of the ß1 or α1 elements resulted in the formation of a reduced but active monomer, without the unfolding of the zinc-binding domain. Collectively, structural insights into the inactive and active conformations, including wild-type and mutant proteins, suggest that the dynamic interactions of the N-terminal segments with their contacting counterpart, the interdomain linker stretch, in the reduced, inactive state are the structural determinants regulating the activation process of the post-translationally regulated chaperone, Hsp33.