Photosynthetic bacteria (PSB) are widely utilised in agriculture to enhance plant growth and crop quality by improving nutrient uptake and phytohormone production. This study aimed to analyse the metagenomic composition of a photo-fermentative bacterial solution derived from fermentation and assess its effects on the growth and yield of Mini Green Cos lettuce. Metagenomic analysis revealed that Bacteroidota (38%) was the most abundant phylum, followed by Proteobacteria (23%), Thermotogota (17%) and Firmicutes (15%). Within Proteobacteria, Alphaproteobacteria was dominant followed by Gammaproteobacteria. At the genus level, Petrimonas (22%), uncultured clones belonging to family Petrotogaceae (17%), Rhodopseudomonas (11%), Rubrivivax (6%), and an unidentified genus from Lentimicrobiaceae (4%) were the most prevalent. These findings highlight the microbial diversity of PSB solution, suggesting its potential role in plant growth promotion. A plant growth experiment was conducted using a Completely Randomised Design (CRD) with four treatments: control (T1), chemical fertiliser (T2), undiluted PSB solution (T3) and PSB solution diluted at a 1:1 ratio (T4), with 10 replicates per treatment. Among all treatments, lettuce irrigated with undiluted PSB solution (T3) exhibited the highest growth rate, yield and total chlorophyll content. However, its performance was not significantly different from that of the chemical fertiliser treatment (T2). These results suggest that PSB can effectively promote plant growth and yield, yielding results comparable to chemical fertilisers. Therefore, photo-fermentative bacterial solutions offer a sustainable and eco-friendly alternative to chemical fertilisers, supporting environmentally conscious agricultural practices.
Two novel endophytic actinomycete strains, NRAIS3T and NRAIS4, belonging to the genus Streptomyces, were isolated from Mitragyna speciosa leaves. Their taxonomic status was determined using a polyphasic approach. Both strains grew at temperatures ranging from 25 to 37 °C and at pH values between 6 and 10. Strain NRAIS3ᵀ tolerated up to 5% (w/v) NaCl, whereas strain NRAIS4 tolerated up to 7% (w/v) NaCl. Both strains contained ll-diaminopimelic acid in their cell-wall peptidoglycan, and their whole-cell hydrolysates contained ribose and glucose. The predominant cellular fatty acids were anteiso-C15:0, anteiso-C17 : 0, iso-C16:0 and iso-C15:0. The polar lipids detected included diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol and phosphatidylinositol mannosides. Based on 16S rRNA gene sequence analysis, strains NRAIS3T and NRAIS4 showed the highest similarity (99.4%) to the type strains Streptomyces fodineus TW1S1T, Streptomyces puniciscabiei DSM 41929T and Streptomyces filipinensis JCM 4369T. The average nucleotide identity based on MUMmer and digital DNA-DNA hybridization values between the genomes of the two strains and those of related type strains were significantly below the Streptomyces species delineation thresholds of 96.7% and 70%, respectively. The ethyl acetate crude extract of NRAIS3T exhibited antibacterial activity against Gram-positive and Gram-negative pathogenic bacteria. It showed the highest activity against Listeria monocytogenes ATCC 7644, followed by Staphylococcus epidermidis ATCC 12228, and Enterococcus faecium ATCC 35667. Liquid chromatography-mass spectrometry and gas chromatography-mass spectrometry analyses revealed diverse antimicrobial metabolites, including aminoquinolines, ergopeptines, isoflavones, hydroxycinnamic acids, N-alkyl piperazines, benzotriazoles, benzimidazoles, phenylacetamides, as well as volatile compounds such as 2,5,5-trimethylcyclohexane-1,3-dione, hexamethyl-cyclotrisiloxane and 1,4-bis(trimethylsilyl) benzene. Based on the taxonomic results, strains NRAIS3T and NRAIS4 represent a novel species within the genus Streptomyces, for which the name Streptomyces mitragynae sp. nov. is proposed. The type strain is NRAIS3T (=LMG 34056T=TBRC 20459T).
Driven by rising global need for fabrics, dye-contaminated wastewater from the textile industry poses a major environmental issue. The existence of dyes in wastewater can negatively affect plants and aquatic animals by reducing light penetration and oxygen levels. The objective of this study was to prepare, characterize, and investigate the removal efficiency of calcium carbonate synthesized from eggshells, comparing its effectiveness with membrane-peeled and unpeeled eggshells. Additionally, the effect of surfactant addition during the synthesis process on calcium carbonate dispersion was investigated. The synthesized calcium carbonate biosorbents were characterized, revealing a rhombohedral crystal structure corresponding to the aragonite phase, one of the calcium carbonate allotropes. The flower-like CaCO3 biosorbents derived from unpeeled eggshells without surfactant dispersant underwent calcination at a temperature of 800 degrees C for 4 h exhibited the highest specific surface area of 171.36 m2 g-1. For methylene blue removal efficiency, the amount of 1 g biosorbent, the initial methylene blue concentration of 100 mg L-1, and the adsorption time of 30 min under pH 7.3 showed the highest methylene blue removal efficiency of 95.44%, corresponding to an adsorption capacity of 95.44 mg g-1. It was effective for reuse up to 5 times with an average removal efficiency ranging from 86.12 to 89.38%. The adsorption behavior followed the Freundlich isotherm and the kinetics fitted well with the pseudo-second-order model. The excellent removal performance of methylene blue dye contaminated both synthetic and textile industry wastewater, with a green chemical approach and cost-effectiveness, demonstrated that eggshell biomaterial was a good candidate for practical application.
ABSTRACT We develop a shrinking projection scheme for approximating solutions of split minimization problems in real Hilbert spaces. Under mild conditions, strong convergence is proved in infinite‐dimensional Hilbert spaces. Numerical experiments in finite‐dimensional settings—standard practice in the numerical analysis literature—are carried out to assess performance. Numerical results show that the algorithm compares favorably with existing methods in terms of convergence rate and reconstruction accuracy. The method is further tested on signal recovery and image restoration tasks, including denoising and deblurring, confirming its practical utility.
A numerical semigroup is a cofinite additive submonoid of the non-negative integers. The study of its gaps has long been central to the theory, with particular emphasis on invariants such as the Frobenius number and the set of pseudo-Frobenius numbers. In this setting, an \emph{isolated gap} is a gap $g$ such that both $g-1$ and $g+1$ belong to the semigroup, and a numerical semigroup is called \emph{perfect} if it has no isolated gaps. Motivated by Smith’s construction of perfect numerical semigroups of embedding dimension three via adjoining the minimum isolated gap of a two-generated semigroup, we derive explicit formulas for the minimum isolated gap of the two-generated numerical semigroups $\langle a, a+n \rangle$ for $n=2,3,4,5,6$, under the natural condition $\gcd(a,a+n)=1$ together with the relevant congruence restrictions on $a$. Our approach combines congruence arguments based on the Euclidean algorithm and the Chinese Remainder Theorem with elementary computations. As a consequence, we obtain constructive families of perfect numerical semigroups of embedding dimension three obtained by adjoining these minimum isolated gaps.
