Vanillin is a flavorful and aromatic secondary metabolite found in vanilla plants. Natural vanillin, produced through processed vanilla beans accounts for scarcely 0.2% of industrial requirements. Vanillin produced via chemical methods and microbial fermentation fills the remaining gap. Among naturally available precursors for biovanillin synthesis, ferulic acid is widely used because of its structural similarity and abundant availability. Herein, various agricultural lignocellulosic by-products (sugarcane bagasse, wheat straw, rice straw, rice bran, and corn cob) were scrutinized for their ferulic acid content, and their biotransformation into biovanillin was examined by solid-state fermentation (SSF). Then, different physicochemical parameters, i.e., moisture content, pH, temperature, inoculum size, and incubation days, were optimized to achieve a high yield of biovanillin using central composite design (CCD) of response surface methodology (RSM). Among agricultural by-products tested, sugarcane bagasse produced 0.029 g/100 g of biovanillin using Enterobacter hormaechei through SSF. After optimization, the highest concentration of biovanillin (0.476 g/100 g) was achieved at a moisture content of 70%, temperature of 37.5 °C, pH 7.5, inoculum size of 4 mL and incubation time of 48 h. The F-value of 6.10 and p-value of 0.002 evidenced the ultimate significance of the model. The significance of the constructed model was supported by the 91.73% coefficient of determination (R²), indicating that the effects of moisture, pH, and temperature were significant. HPLC and FTIR confirmed the sample identification and purity (was reported to be 98.3% pure). In conclusion, sugarcane bagasse appears to be a cost-effective substrate choice for large-scale biovanillin production.

Staphylococcus aureus (S. aureus) is a major causative agent of mastitis and is resistant to many antibiotics. Thus, there is a need to characterize the genetic determinants of S. aureus erythromycin resistance, such as ermA, ermB and ermC. The current study aimed to determine the phenotypic and genotypic erythromycin resistance profile and relatedness of S. aureus recovered from bovine mastitis and humans in close contact. A total of 14 mastitis-infected buffalo milk samples and 16 samples from their respective milkers were collected from different farms of Lahore, Pakistan. The antibiotic resistance profile was determined through the disk diffusion test. The overall prevalence of S. aureus in mastitis-affected buffaloes was found to be 75%, of which 52.1% were resistant to erythromycin and 42.8% to clindamycin. S. aureus isolates recovered from milker nasal samples showed 56.25% resistance to erythromycin and 44% resistance to clindamycin. Genotypic antibiotic resistance profiles were determined from 14 milk samples through PCR. Overall, eight (52.1%), three (21.4%) and five (35.7%) S. aureus isolates were positive for the ermA, ermB and ermC genes, respectively. Moreover, 16 milker nasal S. aureus isolates were also tested for the presence of ermA, ermB and ermC genes. The ermA, ermB and ermC genes were observed in nine(56.7%), five (31.3%) and seven (43.7%) isolates, respectively. A significant association was shown between phenotypic and genotypic erythromycin resistance. The results indicate both that there are sufficient genetic similarities, and the actual transmission of erythromycin resistance genes between these two hosts of S. aureus.