Buletin Veteriner Udayana
Bul. Vet. Udayana. April 2026 Vol. 18 No. 2

THE EFFECT OF CONCENTRATION AND TIME VARIATION OF THE LACTOSE AND SKIM MILK AS INDUCER ON THE EXPRESSION OF RECOMBINANT PROTEIN BOVINE LACTOFERRIN CARBOXY-TERMINUS (BLF CAR)

Febriyan Muji Hartini (Student of the Faculty of Veterinary Medicine, Udayana University, Bukit Jimbaran Campus, Badung, Bali, 80362, Indonesia)
I Gusti Ngurah Kade Mahardika (Biomedical and Veterinary Molecular Biology Laboratory, Faculty of Veterinary Medicine, Udayana University, Jl. Raya Sesetan, Gg. Markisa No. 6, Denpasar, Bali, Indonesia)
I Wayan Masa Tenaya (Veterinary Public Health Laboratory, Faculty of Veterinary Medicine, Udayana University, Jl. P. B. Sudirman, Dangin Puri Klod, Denpasar, Bali, Indonesia)



Article Info

Publish Date
17 May 2026

Abstract

Recombinant bovine lactoferrin (bLf) production has broad potential applications in animal health, particularly as a feed additive and immunomodulatory agent, thereby requiring an efficient and sustainable production system. Lac operon–based expression systems commonly employ isopropyl β-D-1-thiogalactopyranoside (IPTG) as an inducer; however, its high cost and potential to induce metabolic stress limit its applicability for large-scale production. This study aimed to evaluate lactose and skim milk as alternative inducers for recombinant bLf expression. A synthetic bLf CAR gene was cloned into the pGEX-2TK plasmid to generate a GST-bLf CAR fusion protein and expressed under a lac operon–based system. Induction was performed using lactose and skim milk at concentrations of 1%, 2.5%, and 5%, with induction times of 5, 24, and 48 hours, while 0.1 mM IPTG served as the reference inducer. The experimental design followed a randomized block design. Protein expression was analyzed using dot blot, and signal intensity was quantified using ImageJ software. Statistical analysis was conducted using two-way ANOVA followed by Tukey ’s post hoc test. The results demonstrated that inducer type, concentration, and induction time significantly affected the expression intensity of recombinant GST-bLf CAR protein (p < 0.01). Skim milk at a concentration of 2.5% with a 5 hour induction period produced the highest expression level and differed significantly from other treatments. These findings indicate that skim milk is a promising, economical, and practical alternative inducer for recombinant bLf production.

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Journal Info

Abbrev

buletinvet

Publisher

Subject

Immunology & microbiology Public Health Veterinary

Description

FOCUS The journal focused on Veterinary Medicine, Animal Sciences, and Health Studies with various developments. SCOPE Zoonoses, Public Health, One Health, Epidemiology, Reproduction, Virology, Bacteriology, Parasitology, Mycology, Internal Medicine, Surgery, Orthopedics, Vaccines, Genetics, ...