Fe Nanoparticles Enhanced Surfactin Production in Bacillus amyloliquefaciens

Advancing VB12 Production: Insights into Enhancing VB12 Titer in Ensifer adhaerens Casida A through ARTP Mutagenesis and Multiomics Analysis

Ensifer adhaerens, a microorganism recognized for its capacity to synthesize vitamin B12 (VB12), has garnered significant attention in recent years. Nonetheless, its practical application has been limited by low production yields. Atmospheric and room-temperature plasma (ARTP) mutagenesis was utilized to improve VB12 production and examine the associated mechanisms. Three high-yielding mutant strains─BCA-24, BCB-14, and BCC-27─were isolated through multiple rounds of mutagenesis. The VB12 titer of the highly productive mutant strain, BCA-24, rose significantly from 65.64 mg/L to 104.54 mg/L. Genome resequencing identified 14 mutated genes, of which seven (atpA, gntR, fusA, cobQ, ribD, cirA, and UP) were functionally validated through overexpression in wild-type strains and found to positively influence VB12 biosynthesis. Notably, coexpression of the cobQ and UP mutant genes in strain BCA-24 resulted in a VB12 titer of 163.68 mg/L. Transcriptomic analysis indicated that critical pathways related to energy metabolism, S-adenosylmethionine (SAM), 5-aminolevulinic acid (5-ALA), and riboflavin synthesis were significantly upregulated in BCA-24 relative to the wild type. A multiomics approach clarified the mechanisms through which these mutations increase VB12 production, including enhanced transcription and translation, optimized energy supply, and improved product efflux. The identification of novel candidate genes in Ensifer adhaerens, which have not been previously studied, provides valuable resources for future genetic engineering aimed at enhancing VB12 production efficiency. This study offers practical improvements in microbial VB12 production while also delivering essential insights into the genetic and metabolic regulation of this important biosynthetic pathway.

Impact of surfactin on the physicochemical properties of dough and quality of corresponding steamed bread

BACKGROUND

The extensive use of additives in ultra-processed foods presents considerable health concerns. In light of the growing consumer demand for clean labels, a prominent trend is the development of multifunctional food additives that are both natural and beneficial to health. Surfactin, a compound produced by Bacillus subtilis, features both hydrophilic and hydrophobic groups and is noted for its safety, emulsifying and antimicrobial properties. This compound holds significant potential as a multifunctional additive in flour-based products. The present study aimed to evaluate the effects of surfactin on the physicochemical properties of dough and the quality of steamed bread, as well as to investigate the underlying mechanisms.

RESULTS

The results showed that the addition of surfactin significantly improved its rheological properties, increased elasticity and viscosity, improved extension resistance and increased disulfide bonding content in dough (P < 0.05), subsequently stabilizing the gluten network structure. With a 0.3% surfactin addition, the digestibility of steamed bread significantly reduced. After storing for 7 days, surfactin inhibited water migration, reduced the transfer from bound water to free water, delayed starch recrystallization, improved resistance to starch retrogradation and markedly extended the shelf life in steamed bread.

CONCLUSION

The addition of surfactin improved the quality of steamed bread through stabilizing the gluten network structure and improving storage properties, presenting it as a promising natural, multifunctional food additive for flour product innovation. © 2024 Society of Chemical Industry.

Optimizing surfactin yield in Bacillus velezensis BN to enhance biocontrol efficacy and rhizosphere colonization

Introduction

Surfactins, a class of lipopeptide biosurfactants secreted by plant growth-promoting rhizobacteria (PGPR), have garnered significant attention due to their dual functionality in promoting plant growth and controlling plant diseases. Their potential as biopesticides is underscored by their unique physicochemical properties and biological activities. However, the practical application of surfactin is currently limited by its low yield in natural strains.

Methods

This study aimed to optimize the culture conditions for Bacillus velezensis BN, a strain with exceptional biocontrol properties, to enhance its surfactin yield. Critical factors, including nitrogen sources and amino acid supplementation, were systematically investigated to determine their impact on surfactin production.

Results

The study revealed that nitrogen sources and amino acid supplementation were pivotal factors influencing surfactin yield. Compared to the baseline, these factors resulted in a remarkable 5.94-fold increase in surfactin production. Furthermore, a positive correlation was established between surfactin yield and biocontrol efficacy. Enhanced surfactin yield was associated with improved antifungal activity, biofilm formation, and rhizosphere colonization capacity of B. velezensis BN on potato plantlets.

Discussion

These findings provide novel insights into the practical application of surfactin and establish a scientific foundation for the development of innovative and eco-friendly antifungal agents suitable for agricultural use. The results demonstrate that optimizing culture conditions can significantly enhance surfactin yield and biocontrol efficacy, thereby highlighting the potential for sustainable agricultural practices.

Improving Surfactin Production in Bacillus subtilis 168 by Metabolic Engineering

Surfactin is widely used in the petroleum extraction, cosmetics, biopharmaceuticals and agriculture industries. It possesses antibacterial and antiviral activities and can reduce interfacial tension. Bacillus are commonly used as production chassis, but wild-type Bacillus subtilis 168 cannot synthesise surfactin. In this study, the phosphopantetheinyl transferase (PPTase) gene sfp* (with a T base removed) was overexpressed and enzyme activity was restored, enabling B. subtilis 168 to synthesise surfactin with a yield of 747.5 ± 6.5 mg/L. Knocking out ppsD and yvkC did not enhance surfactin synthesis. Overexpression of predicted surfactin transporter gene yfiS increased its titre to 1060.7 ± 89.4 mg/L, while overexpression of yerP, ycxA and ycxA-efp had little or negative effects on surfactin synthesis, suggesting YfiS is involved in surfactin efflux. By replacing the native promoter of the srfA operon encoding surfactin synthase with three promoters, surfactin synthesis was significantly reduced. However, knockout of the global transcriptional regulator gene codY enhanced the surfactin titre to 1601.8 ± 91.9 mg/L. The highest surfactin titre reached 3.89 ± 0.07 g/L, with the yield of 0.63 ± 0.02 g/g DCW, after 36 h of fed-batch fermentation in 5 L fermenter. This study provides a reference for further understanding surfactin synthesis and constructing microbial cell factories.

Available strategies for improving the biosynthesis of surfactin: a review

Surfactin is an excellent biosurfactant with a wide range of application prospects in many industrial fields. However, its low productivity and high cost have largely limited its commercial applications. In this review, the pathways for surfactin synthesis in Bacillus strains are summarized and discussed. Further, the latest strategies for improving surfactin production, including: medium optimization, genome engineering methods (rational genetic engineering, genome reduction, and genome shuffling), heterologous synthesis, and the use of synthetic biology combined with metabolic engineering approaches to construct high-quality artificial cells for surfactin production using xylose, are described. Finally, the prospects for improving surfactin synthesis are discussed in detail.

Recent advances and prospects of Bacillus amyloliquefaciens as microbial cell factories: from rational design to industrial applications

Bacillus amyloliquefaciens is one of the most characterized Gram-positive bacteria. This species has unique characteristics that are beneficial for industrial applications, including its utilization of: cheap carbon as a substrate, a transparent genetic background, and large-scale robustness in fermentation. Indeed, the productivity characteristics of B. amyloliquefaciens have been thoroughly analyzed and further optimized through systems biology and synthetic biology techniques. Following the analysis of multiple engineering design strategies, B. amyloliquefaciens is now considered an efficient cell factory capable of producing large quantities of multiple products from various raw materials. In this review, we discuss the significant potential advantages offered by B. amyloliquefaciens as a platform for metabolic engineering and industrial applications. In addition, we systematically summarize the recent laboratory research and industrial application of B. amyloliquefaciens, including: relevant advances in systems and synthetic biology, various strategies adopted to improve the cellular performances of synthetic chemicals, as well as the latest progress in the synthesis of certain important products by B. amyloliquefaciens. Finally, we propose the current challenges and essential strategies to usher in an era of broader B. amyloliquefaciens use as microbial cell factories.

Nano-bioremediation: an eco-friendly and effective step towards petroleum hydrocarbon removal from environment

Global concern about petroleum hydrocarbon pollution has intensified and gained scientific interest due to its noxious nature, high persistence in environmental matrices, and low degradability. One way to address this is by combining remediation techniques that could overcome the constraints of traditional physio-chemical and biological remediation strategies. The upgraded concept of bioremediation to nano-bioremediation in this direction offers an efficient, economical, and eco-friendly approach to mitigate petroleum contaminants. Here, we review the unique attributes of different types of nanoparticles and their synthesis procedures in remediating various petroleum pollutants. This review also highlights the microbial interaction with different metallic nanoparticles and their consequential alteration in microbial as well as enzymatic activity which expedites the remediating process. Besides, the latter part of the review explores the application of petroleum hydrocarbon degradation and the application of nano supports as immobilizing agents for microbes and enzymes. Further, the challenges and the future prospects of nano-bioremediation have also been discussed.

Cassava wastewater valorization for the production of biosurfactants: surfactin, rhamnolipids, and mannosileritritol lipids

The global production of cassava was estimated at ca. 303 million tons. Due to this high production, the cassava processing industry (cassava flour and starch) generates approximately ca. 0.65 kg of solid residue and ca. 25.3 l of wastewater per kg of fresh processed cassava root. The composition of the liquid effluent varies according to its origin; for example, the effluent from cassava flour production, when compared to the wastewater from the starch processing, presents a higher organic load (ca. 12 times) and total cyanide (ca. 29 times). It is worthy to highlight the toxicity of cassava residues regarding cyanide presence, which could generate disorders with acute or chronic symptoms in humans and animals. In this sense, the development of simple and low-cost eco-friendly methods for the proper treatment or reuse of cassava wastewater is a challenging, but promising path. Cassava wastewater is rich in macro-nutrients (proteins, starch, sugars) and micro-nutrients (iron, magnesium), enabling its use as a low-cost culture medium for biotechnological processes, such as the production of biosurfactants. These compounds are amphipathic molecules synthesized by living cells and can be widely used in industries as pharmaceutical agents, for microbial-enhanced oil recovery, among others. Amongst these biosurfactants, surfactin, rhamnolipids, and mannosileritritol lipids show remarkable properties such as antimicrobial, biodegradability, demulsifying and emulsifying capacity. However, the high production cost restricts the massive biosurfactant applications. Therefore, this study aims to present the state of the art and challenges in the production of biosurfactants using cassava wastewater as an alternative culture medium.

Oxygen mass transfer enhancement by activated carbon particles in xylose fermentation media

In this work, the effect of activated carbon particles on the production of xylonic acid from xylose by Gluconobacter oxydans in a stirred tank bioreactor was investigated. The enhancement of the oxygen transfer coefficient by activated carbon particles was experimentally evaluated under different solids volume fractions, agitation and aeration rates conditions. The experimental conditions optimized by response surface methodology (agitation speed 800 rpm, aeration rate 7 L min^-1, and activated carbon 0.002%) showed a maximum oxygen transfer coefficient of 520.7 h^-1, 40.4% higher than the control runs without activated carbon particles. Under the maximum oxygen transfer coefficient condition, the xylonic acid titer reached 108.2 g/L with a volumetric productivity of 13.53 g L^-1 h^-1 and a specific productivity of 6.52 g/g_x/h. In conclusion, the addition of activated carbon particles effectively enhanced the oxygen mass transfer rate. These results demonstrate that activated carbon particles enhanced cultivation for xylonic acid production an inexpensive and attractive alternative.

New aspects of lipopeptide-incorporated nanoparticle synthesis and recent advancements in biomedical and environmental sciences: a review

The toxicity of metal nanoparticles has introduced promising research in the current scenario since an enormous number of people have been potentially facing this problem in the world. The extensive attention on green nanoparticle synthesis has been focussed on as a vital step in bio-nanotechnology to improve biocompatibility, biodegradability, eco-friendliness, and huge potential utilization in various environmental and clinical assessments. Inherent influence on the study of green nanoparticles plays a key role to synthesize the controlled and surface-influenced molecule by altering the physical, chemical, and biological assets with the provision of various precursors, templating/co-templating agents, and supporting solvents. However, in this article, the dominant characteristics of several kinds of lipopeptide biosurfactants are discussed to execute a critical study of factors affecting synthesis procedure and applications. The recent approaches of metal, metal oxide, and composite nanomaterial synthesis have been deliberated as well as the elucidation of the reaction mechanism. Furthermore, this approach shows remarkable boosts in the production of nanoparticles with the very less employed harsh and hazardous processes as compared to chemical or physical method-based nanoparticle synthesis. This study also shows that the advances in strain selection for green nanoparticle production could be a worthwhile and strong economical approach in futuristic medical science research.

Magnetite-Bacillus subtilis synergy on the metabolic selection of products in electrofermentation system

The study examines the role of magnetite (1-150 mg/L) at the interface of Bacillus subtilis-electrode under poised-condition (-0.2 V) for product-formation and catalytic-conduct with the relative-gene-expression encoding lactate dehydrogenase (lctE), pyruvate dehydrogenase (pdhA), acetate kinase (ackA), pyruvate carboxylase (pycA), and NADH dehydrogenase (ndh). The magnetite load of 25 mg/L showed positive influence on acidogenesis resulting in H₂ production of 264.7 mol/mL and fatty acids synthesis of 3.6 g/L. Additionally, this condition showed higher succinic acid productivity (2.8 g/L) which correlates with the upregulated pycA gene and fumarate to succinate redox peak. With 10 mg/L loading, production of higher acetic acid (3.1 g/L) along with H₂ (181.6 mol/mL) was depicted wherein upregulation of pdhA, ackA and ndh genes was observed. In absence of magnetite, lctE gene was upregulated which resulted higher lactate production. The findings suggest that the mutual-interactions between magnetite-active sites of specific enzymes enhances the biocatalytic activity triggering product-formation.

Structures and antitumor activities of ten new and twenty known surfactins from the deep-sea bacterium Limimaricola sp. SCSIO 53532

Surfactins are natural biosurfactants with myriad potential applications in the areas of healthcare and environment. However, surfactins were almost exclusively produced by the bacterium Bacillus species in previous reported literatures, together with difficulty in isolating pure monomer, which resulted in making extensive effort to remove duplication and little discovery of new surfactins in recent years. In the present study, the result of Molecular Networking indicated that Limimaricola sp. SCSIO 53532 might well be a potential resource for surfacin-like compounds based on OSMAC strategy. To search for new surfactins with significant biological activity, further study was undertaken on the strain. As a result, ten new surfactins (1-10), along with twenty known surfactins (11-30), were isolated from the ethyl acetate extract of SCSIO 53532. Their chemical structures were established by detailed 1D and 2D NMR spectroscopy, HRESIMS data, secondary ion mass spectrometry (MS/MS) analysis, and chemical degradation (Marfey's method) analysis. Cytotoxic activities of twenty-seven compounds against five human tumor cell lines were tested, and five compounds showed significant antitumor activities with IC₅₀ values less than 10 μM. Furtherly, analysis of structure-activity relationships revealed that the branch of side chain, the esterification of Glu or Asp residue, and the amino acid residue of position 7 possessed a great influence on antitumor activity.

The beauty of biocatalysis: sustainable synthesis of ingredients in cosmetics

Covering: 2015 up to July 2021The market for cosmetics is consumer driven and the desire for green, sustainable and natural ingredients is increasing. The use of isolated enzymes and whole-cell organisms to synthesise these products is congruent with these values, especially when combined with the use of renewable, recyclable or waste feedstocks. The literature of biocatalysis for the synthesis of ingredients in cosmetics in the past five years is herein reviewed.

Effect of zinc oxide nanoparticle supplementation on the enhanced production of surfactin and iturin lipopeptides of endophytic Bacillus sp. Fcl1 and its ameliorated antifungal activity

BACKGROUND

Lipopeptides from the Bacillus spp. possess an excellent spectrum of antimicrobial properties which make them suitable candidates to be explored for the food, agricultural, pharmaceutical and biotechnological applications. As the low yield of the lipopeptides limits their applications, methods to enhance their production are highly significant.

RESULTS

In this study, extracts prepared from endophytic Bacillus sp. Fcl1 cultured in the presence of various supplements were screened for antifungal activity against Pythium aphanidermatum. From the results, the supplementation of carbon sources and zinc oxide nanoparticles (ZnONPs) was found to have an enhancement effect on the antifungal activity of Bacillus sp. Fcl1. Among these, the highest antifungal activity (73.2%) could be observed for the Fcl1 sample cultured with 5 mg L^-1 of ZnONP supplementation. The growth of Fcl1 in the presence of ZnONPs also indicated its compatibility with the nano-supplement in the concentration range used. By liquid chromatography quadrupole time-of-flight mass spectrometry (LC-Q-TOF-MS) analysis, the synthesis of increased numbers of lipopeptide surfactin derivatives could be identified from the extracts of Fcl1 prepared from the carbon sources and ZnONP-supplemented cultures. In addition to the surfactin derivatives, the presence of another lipopeptide iturin was also detected from the extracts of Fcl1 cultured with ZnONPs.

CONCLUSION

ZnONP supplementation was found to enhance antifungal activity and lipopeptide production in the Bacillus sp. Fcl1. The use of nanoparticles to enhance the antifungal mechanisms of Fcl1 as observed in the study provides novel insights to explore its applications for sustainable agricultural productivity.