Enhancing production of lipase MAS1 from marine Streptomyces sp. strain in Pichia pastoris by chaperones co-expression

Background: A thermostable lipase MAS1 from marine Streptomyces sp. strain was considered as a potential biocatalyst for industrial application, but its production level was relatively low. Here, the effect of chaperones co-expression on the secretory expression of lipase MAS1 in Pichia pastoris was investigated. Result: Co-expression of protein disulfide isomerase (PDI), HAC1 and immunoglobulin binding protein could increase the expression level of lipase MAS1, whereas co-expression of Vitreoscilla hemoglobin showed a negative effect to the lipase MAS1 production. Among them, PDI co-expression increased lipase MAS1 expression level by 1.7-fold compared to the control strain harboring only the MAS1 gene. Furthermore, optimizing production of lipase MAS1 with Pichia pastoris strain X-33/MAS1-PDI in a 30-L bioreactor were conducted. Lower induction temperature was found to have a benefit effect for lipase MAS1 production. Lipase activity at 24 and 22\ub0C showed 1.7 and 2.1-fold to that at 30\ub0C, respectively. Among the induction pH tested, the highest lipase activity was obtained at pH 6.0 with activity of 440 U/mL after 144 h fermentation. Conclusion: Our work showed a good example for improving the production of recombinant enzymes in Pichia pastoris via chaperon co-expression and fermentation condition optimization

Synthesis of conjugated linoleic acid-rich triacylglycerols by immobilized mutant lipase with excellent capability and recyclability

Conjugated linoleic acid (CLA)-rich triacylglycerols (TAG) have received significant attention owing to their health promoting properties. In this study, CLA-rich TAG were successfully synthesized by an immobilized mutant lipase (MAS1-H108A)-catalyzed esterification of CLA-rich fatty acids and glycerol under vacuum. MAS1-H108A was first immobilized onto ECR1030 resin. Results showed that the lipase/support ratio of 41 mg/g was suitable for the immobilization and the thermostability of immobilized MAS1-H108A was greatly enhanced. Subsequently, the immobilized MAS1-H108A was employed for the synthesis of CLA-rich TAG and 95.21% TAG with 69.19% CLA was obtained under the optimized conditions. The TAG content (95.21%) obtained by immobilized MAS1-H108A is the reported highest value thus far, which was significantly higher than that (9.26%) obtained by Novozym 435 under the same conditions. Although the TAG content comparable to the results obtained in this study could also be obtained by Novozym 435, the used enzyme amount is approximately 5-fold of the immobilized MAS1-H108A. Additionally, the immobilized MAS1-H108A exhibited excellent recyclability during esterification retaining 95.11% of its initial activity after 10 batches. Overall, such immobilized mutant lipase with superior esterification activity and recyclability has the potential to be used in oils and fats industry

SCULPTOR: Skeleton-Consistent Face Creation Using a Learned Parametric Generator

Recent years have seen growing interest in 3D human faces modelling due to its wide applications in digital human, character generation and animation. Existing approaches overwhelmingly emphasized on modeling the exterior shapes, textures and skin properties of faces, ignoring the inherent correlation between inner skeletal structures and appearance. In this paper, we present SCULPTOR, 3D face creations with Skeleton Consistency Using a Learned Parametric facial generaTOR, aiming to facilitate easy creation of both anatomically correct and visually convincing face models via a hybrid parametric-physical representation. At the core of SCULPTOR is LUCY, the first large-scale shape-skeleton face dataset in collaboration with plastic surgeons. Named after the fossils of one of the oldest known human ancestors, our LUCY dataset contains high-quality Computed Tomography (CT) scans of the complete human head before and after orthognathic surgeries, critical for evaluating surgery results. LUCY consists of 144 scans of 72 subjects (31 male and 41 female) where each subject has two CT scans taken pre- and post-orthognathic operations. Based on our LUCY dataset, we learn a novel skeleton consistent parametric facial generator, SCULPTOR, which can create the unique and nuanced facial features that help define a character and at the same time maintain physiological soundness. Our SCULPTOR jointly models the skull, face geometry and face appearance under a unified data-driven framework, by separating the depiction of a 3D face into shape blend shape, pose blend shape and facial expression blend shape. SCULPTOR preserves both anatomic correctness and visual realism in facial generation tasks compared with existing methods. Finally, we showcase the robustness and effectiveness of SCULPTOR in various fancy applications unseen before.Comment: 16 page, 13 fig

The Lid Domain in Lipases: Structural and Functional Determinant of Enzymatic Properties

Lipases are important industrial enzymes. Most of the lipases operate at lipid–water interfaces enabled by a mobile lid domain located over the active site. Lid protects the active site and hence responsible for catalytic activity. In pure aqueous media, the lid is predominantly closed, whereas in the presence of a hydrophobic layer, it is partially opened. Hence, the lid controls the enzyme activity. In the present review, we have classified lipases into different groups based on the structure of lid domains. It has been observed that thermostable lipases contain larger lid domains with two or more helices, whereas mesophilic lipases tend to have smaller lids in the form of a loop or a helix. Recent developments in lipase engineering addressing the lid regions are critically reviewed here. After on, the dramatic changes in substrate selectivity, activity, and thermostability have been reported. Furthermore, improved computational models can now rationalize these observations by relating it to the mobility of the lid domain. In this contribution, we summarized and critically evaluated the most recent developments in experimental and computational research on lipase lids

Deep eutectic solvents enable the enhanced production of n-3 PUFA-enriched triacylglycerols

Efficient synthesis of n‐3 PUFA‐enriched triacylglycerol (TAG) by the esterification of glycerol with n‐3 PUFA in deep eutectic solvents (DES) is reported. There was a 1.2‐fold increase of TAG yield in DES compared with that in the solvent‐free system. Adsorption of the produced water by DES during esterification contributed to enhance the conversion efficiency by changing the reaction equilibrium. DES also served as an effective solvent for enriching the n‐3 PUFA of TAG in the upper layer of reaction media. A TAG yield of 55% was achieved under the optimal condition. Practical Applications: Enzymatic synthesis of n‐3 PUFA‐enriched triacylglycerol (TAG) is challenged by low yields. Here, deep eutectic solvents show great potential for enhancing the production of n‐3 PUFA‐enriched TAG

Biochemical Properties and Potential Applications of Recombinant Leucine Aminopeptidase from Bacillus kaustophilus CCRC 11223

Experiments were carried out to investigate the effects of various factors on the activity and conformation of recombinant leucine aminopeptidase of Bacillus kaustophilus CCRC 11223 (BkLAP) and potential utilization of BkLAP in the hydrolysis of anchovy protein. Optimal temperature and pH of BkLAP were 70 °C and 8.0 in potassium-phosphate buffer, respectively, and the activity was strongly stimulated by Ni2+, followed by Mn2+ and Co2+. Conformational studies via circular dichroism spectroscopy indicated that various factors could influence the secondary structure of BkLAP to different extents and further induce the changes in enzymatic activity. The secondary structure of BkLAP was slightly modified by Ni2+ at the concentration of 1×10−4 M, however, significant changes on the secondary structures of the enzyme were observed when Hg2+ was added to the concentration of 1×10−4 M. The potential application of BkLAP was evaluated through combination with the commercial or endogenous enzyme to hydrolysis the anchovy protein. Results showed that combining the BkLAP with other enzymes could significantly increase the degree of hydrolysis and amino acid component of hydrolysate. In this regard, BkLAP is a potential enzyme that can be used in the protein hydrolysate industry

Optimal Production and Biochemical Properties of a Lipase from Candida albicans

Lipases from microorganisms have multi-faceted properties and play an important role in ever-growing modern biotechnology and, consequently, it is of great significance to develop new ones. In the present work, a lipase gene from Candida albicans (CaLIP10) was cloned and two non-unusual CUG serine codons were mutated into universal codons, and its expression in Pichia pastoris performed optimally, as shown by response surface methodology. Optimal conditions were: initial pH of culture 6.86, temperature 25.53 °C, 3.48% of glucose and 1.32% of yeast extract. The corresponding maximal lipolytic activity of CaLIP10 was 8.06 U/mL. The purified CaLIP10 showed maximal activity at pH 8.0 and 25 °C, and a good resistance to non-ionic surfactants and polar organic solvent was noticed. CaLIP10 could effectively hydrolyze coconut oil, but exhibited no obvious preference to the fatty acids with different carbon length, and diacylglycerol was accumulated in the reaction products, suggesting that CaLIP10 is a potential lipase for the oil industry

Single cell atlas for 11 non-model mammals, reptiles and birds.

The availability of viral entry factors is a prerequisite for the cross-species transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Large-scale single-cell screening of animal cells could reveal the expression patterns of viral entry genes in different hosts. However, such exploration for SARS-CoV-2 remains limited. Here, we perform single-nucleus RNA sequencing for 11 non-model species, including pets (cat, dog, hamster, and lizard), livestock (goat and rabbit), poultry (duck and pigeon), and wildlife (pangolin, tiger, and deer), and investigated the co-expression of ACE2 and TMPRSS2. Furthermore, cross-species analysis of the lung cell atlas of the studied mammals, reptiles, and birds reveals core developmental programs, critical connectomes, and conserved regulatory circuits among these evolutionarily distant species. Overall, our work provides a compendium of gene expression profiles for non-model animals, which could be employed to identify potential SARS-CoV-2 target cells and putative zoonotic reservoirs

Control of a class of chaotic systems by a stochastic delay method

summary:A delay stochastic method is introduced to control a certain class of chaotic systems. With the Lyapunov method, a suitable kind of controllers with multiplicative noise is designed to stabilize the chaotic state to the equilibrium point. The method is simple and can be put into practice. Numerical simulations are provided to illustrate the effectiveness of the proposed controllable conditions