Asian Journal of Biotechnology and Genetic Engineering

Postbiotics as Emerging Functional Biotics: Antimicrobial Potential, Production Strategies, and Mechanistic Insights

2026-03-21T07:55:28+00:00

Background: Postbiotics have recently emerged as a promising category of functional biotics derived from microbial fermentation. Unlike probiotics, postbiotics consist of non-viable microbial cells, metabolites, and structural components that exert biological effects without requiring microbial viability. Their improved stability, safety profile, and defined biochemical composition have generated increasing interest for applications in biotechnology, food science, and therapeutic development.

Methods: This review systematically analyzed recent literature on postbiotics, focusing on their microbial sources, bioactive components, production strategies, characterization methods, antimicrobial mechanisms, and potential therapeutic applications. Relevant studies were evaluated to summarize current advances in fermentation technologies, downstream processing, and analytical approaches used for postbiotic identification and functional evaluation.

Results: Evidence from recent studies indicates that postbiotics contain diverse bioactive compounds, including short-chain fatty acids, bacteriocins, exopolysaccharides, enzymes, peptides, and cell wall fragments. These components contribute to multiple biological effects, particularly antimicrobial activity against pathogenic microorganisms, modulation of host immune responses, improvement of intestinal barrier function, and regulation of metabolic pathways. Compared with live probiotics, postbiotics demonstrate greater physicochemical stability, longer shelf life, and reduced risk of infection, making them more suitable for incorporation into pharmaceutical formulations, functional foods, and cosmetic products.

Conclusion: Postbiotics represent a promising next-generation functional biotic with significant antimicrobial and therapeutic potential. Advances in microbial fermentation, molecular characterization, and precision bioprocessing are expected to facilitate the development of standardized postbiotic formulations for biomedical and industrial applications.

Dose-dependent Effects of Thyroxine (T4) Immersion on Growth and Survival of Giant Gourami (Osphronemus goramy) Fry

2026-01-16T11:29:50+00:00

The immersion gourami larvae and fry in a thyroxine hormone solution requires an optimal dosage suitable for larval or fry growth and survival. Excessive doses of T4 accelerate the larvae's metabolism and damage the nervous system, liver, and heart, leading to larval mortality. Although gourami fish is a significant economic commodity in Indonesia, slow fish growth and fry mortality rates hinder fingerlings production. The objective of this study was to determine the optimal thyroxine hormone dosage to promote Osphronemus goramy fry growth and survival (10 days after hatching). Six thyroxine dosage treatments (A: 0.00 mg/L; B: 0.25 mg/L; C: 0.5 mg/L; D: 0.75 mg/L; E: 1.00 mg/L; and F: 1.25 mg/L) and four replications were used in this completely randomized design. The gourami fry's weight, length, and survival over the course of 60 days of maintenance are test parameters. The results of the analysis of variance test revealed that immersion gourami fry with thyroxine considerably improved their growth and survival when compared to non-immersed fry. The Duncan's Multiple Range test showed that a thyroxine hormone dosage of 1.00 mg/L produced an optimal survival rate of 91% and growth body length and weight of 8.04 cm and 9.2 g. The results of this study indicate that growth hormone receptor gene expression is present in the target tissues of the thyroxine hormone. This indication can be seen in each thyroxine dose treatment resulting in increased fry weight compared to without thyroxine.

Biochemical and Antioxidant Modulation by Solvent Fractions of Azanza garckeana Leaf Extract in Streptozotocin-Induced Diabetic Rats

2026-01-27T12:23:30+00:00

Diabetes mellitus (DM) is a metabolic syndrome. Diabetes has become more common in recent years. Chemically generated drugs are used to lessen the effects of DM and its following repercussions due to unpleasant side effects such as weight gain, gastrointestinal issues, and heart failure. On the other hand, medicinal plants are considered safe, accessible, and affordable anti-diabetic remedies. This research aims to determine the antidiabetic effects of the different solvent fractions of Azanza garckeana in streptozotocin (STZ)-induced diabetic rats. Twenty-eight (28) white albino rats weighing about 220–250g were used for this study and diabetes was induced by intraperitoneal injection of 55 mg/kg body weight of Streptozotocin feed with high fat diet. The albino rats were randomly divided into seven (7) groups which are as follows: Groups; normal control, diabetic control groups, standard drug (metformin), diabetes treated, diabetes treated n-hexane, diabetes treated ethyl acetate, diabetes treated methanol, and diabetes treated aqueous with Azanza garckeana extracts (100 mg/kg) was administered for 28 days. Biochemical parameters, including fasting blood glucose, lipid profile, bilirubin, electrolytes, liver enzymes, and antioxidant enzymes were assessed. The results showed that the methanol fraction of Azanza garckeana leaf significantly reduced blood glucose levels while protein and albumin biomarkers were significantly (P ≤0.005), increased across groups. It also improved the lipid profiles, restored liver enzyme activity, and enhanced antioxidant defense mechanisms and at the same time a significant positive impact on hematological parameters. These findings support the traditional use of Azanza garckeana leaf in diabetes management and suggest its therapeutic potential for metabolic disorders.

Isolation and Characterization of Antimicrobial Phenolic Compounds from Garcinia kola in Nigeria

2026-01-29T09:55:39+00:00

Garcinia kola is widely recognized for its medicinal value across Sub-Saharan Africa, yet there remains limited clarity on the specific phenolic constituents responsible for its antimicrobial effects. While previous studies have reported broad antibacterial and antifungal activity, the detailed characterization of bioactive compounds from Nigerian seeds remains incomplete. This study aimed to address this gap by extracting, isolating, and profiling phenolic constituents from seeds collected in Ibadan, Nigeria, and evaluating their antimicrobial potential. Seed powders were subjected to solvent extraction followed by chromatographic fractionation and purification. Isolated compounds were identified using FT-IR, MS, NMR, HPLC-DAD, and GC-MS. Antimicrobial activity was assessed using agar diffusion and broth microdilution assays against selected clinical and reference microorganisms. The extracts demonstrated substantial antibacterial and antifungal effects, with stronger activity against Gram-positive bacteria. Three major isolates were identified as cycloartenol, 24-methylenecycloartanol, and garcinianin, with the triterpenoids exhibiting the highest potency. The findings indicate that Nigerian G. kola seeds contain diverse phenolic and terpenoid compounds with promising antimicrobial properties, supporting traditional applications and highlighting their potential for drug development. Further research should investigate mechanisms of action, toxicity, and in vivo effectiveness to support future pharmacological use.

Effect of Ethyl Acetate Leaf Extract of Gliricidia sepium on Thyroid and Reproductive Hormone Profiles in Wistar Rats

2026-02-13T07:43:59+00:00

Aim: This study investigated the effects of oral administration of ethyl acetate leaf extract of Gliricidia sepium on thyroid and reproductive hormone profiles in Wistar rats.

Study Design: Completely randomized controlled experimental study.

Place and Duration of Study: The study was conducted at the Animal House, Faculty of Pharmaceutical Sciences, and the Chemical Pathology Laboratory, School of Medical Laboratory Science, Usmanu Danfodiyo University, Sokoto, Nigeria, between May 2024 and October 2025.

Methodology: The ethyl acetate fraction was obtained from a crude methanol extract. Acute oral toxicity was assessed using Lorke’s method. Twelve male Wistar rats were assigned into four groups. In Phase I, groups I–III received 10, 100, and 1000 mg/kg body weight of the extract, respectively, while group IV served as the control. In Phase II, three rats received single oral doses of 1600, 2900, and 5000 mg/kg body weight.

Forty-eight adult Wistar rats (24 males and 24 females) were split up into four groups for the sub-chronic toxicity investigation. Group I received normal saline, whereas Groups II-IV received the extract at doses of 500, 1000, and 1500 mg/kg body weight daily for 28 days. Samples of blood were taken in order to analyze hormones. The microplate enzyme-linked immunosorbent assay (ELISA) method was used to measure hormone levels. The Statistical Package for Social Science (SPSS) for Windows, version 23.0 (SPSS Inc., Chicago, IL, USA), was used to analyze the data collected for this study.

Results: The extract had an oral median lethal dose (LD₅₀) of more than 5000 mg/kg body weight. Sub-chronic treatment did not result in significant alterations (p > 0.05) in TSH, T₃, T₄, testosterone, progesterone, prolactin, and FSH. Variations observed in LH and estradiol levels were attributable to physiological sex-related differences.

Conclusion: Oral administration of ethyl acetate leaf extract of Gliricidia sepium at therapeutic doses appears relatively safe and does not adversely affect thyroid or reproductive hormone function in Wistar rats.

The Impact of Extrusion Process Variables on the Physicochemical and Sensory Qualities of Maize (Zea mays), Bambara Groundnut (Vigna subterranea), and Sweet Potato (Ipomoea batatas) Based Extruded Products

2026-02-17T09:17:51+00:00

Snack foods are typically designed to be portable, quick, and satisfying. High-temperature extrusion for a short duration "minimizes losses in vitamins and amino acids". Since protein-energy malnutrition and micronutrient deficiencies are widely prevalent, the utilization of underutilized legumes (bambara groundnuts) for the supplementation of starch-based foods is essential. This work determined the effect of extrusion variables on the physicochemical and sensory properties of the snacks. The flour particle size, moisture level, screw speed, and die diameter (4mm) were kept constant throughout the process while the feed composition and barrel temperatures were varied. The expansion ratio and bulk density of the extrudate ranged from 0.51±0.44 to 0.807±0.012 and 0.727±0.111 to 0.803±0.033 gcm^-3 respectively. As for proximate composition, the moisture content ranged from (5.167±0.116 to 4.00±0.1661 %), Protein (8.623±0.337 to 13.950±0.812%), Fat (1.833±0.011 to 4.300±0.112%), crude fiber (2.587±0.112 to 3.40±0.178%), Ash (0.833±0.012 to 1.817±0.091%) and carbohydrate (73.09±0.881 to 80.460±0.112%), respectively all at varying temperatures and feed compositions. The sensory attributes of the snack ranged from 3.823±0.119 to 6.730±0.073 for appearance, 3.73±0.091 to 6.583±0.073 for flavour, from 4.00±0.571 to 4.840±0.331 for texture, with a significant difference as influenced by the feed compositions and barrel temperatures but sample Fc₃Bt₃ had the highest percentage of overall acceptability 6.667±0.117 as influenced by extrusion variables.

In-vitro Antibacterial Activity of Hibiscus sabdariffa Calyx Extracts against Multidrug-resistant Escherichia coli from Patients with Urinary Tract Infections in Katsina State, Nigeria

2026-03-05T06:47:23+00:00

Background: Urinary tract infections (UTIs) are among the most prevalent bacterial infections globally, with Escherichia coli being the leading etiological agent. The increasing occurrence of multidrug-resistant (MDR) uropathogenic E. coli (UPEC) has significantly compromised the effectiveness of commonly used antibiotics, particularly in low- and middle-income countries.

Aims: This study aimed to evaluate the antibacterial activity of aqueous and ethanol calyx extracts of Hibiscus sabdariffa against MDR E. coli isolated from patients with urinary tract infections attending General Hospital Dutsin-Ma, Katsina State, Nigeria.

Method: Fifty midstream urine samples were collected and processed using standard culture, microscopy, and biochemical identification techniques. Antibiotic susceptibility testing was performed using the Kirby–Bauer disc diffusion method in accordance with Clinical and Laboratory Standards Institute guidelines. Phytochemical screening of H. sabdariffa extracts was conducted, and antibacterial activity was assessed using the agar well diffusion assay, followed by determination of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC).

Results: Ten (20%) E. coli isolates were recovered, with a higher prevalence among female patients (70%). High resistance rates were observed against cefotaxime (80%), ciprofloxacin (70%), and ampicillin (60%), while all isolates remained susceptible to nitrofurantoin (100%). Four isolates were classified as MDR. Both aqueous and ethanol extracts of H. sabdariffa demonstrated concentration-dependent antibacterial activity against MDR isolates, with the ethanol extract showing greater potency (MIC 25 mg/mL; MBC 50 mg/mL) compared to the aqueous extract (MIC 50 mg/mL; MBC 100 mg/mL).

Conclusion: The findings indicate that H. sabdariffa possesses significant antibacterial activity against MDR UPEC and may serve as a potential complementary antimicrobial agent for urinary tract infections.