Batch culture and repeated-batch culture of Cunninghamella bainieri 2A1 for lipid production as a comparative study

AbstractThis research was performed based on a comparative study on fungal lipid production by a locally isolated strain Cunninghamella bainieri 2A1 in batch culture and repeated-batch culture using a nitrogen-limited medium. Lipid production in the batch culture was conducted to study the effect of different agitation rates on the simultaneous consumption of ammonium tartrate and glucose sources. Lipid production in the repeated-batch culture was studied by considering the effect of harvesting time and harvesting volume of the culture broth on the lipid accumulation. The batch cultivation was carried out in a 500ml Erlenmeyer flask containing 200ml of the fresh nitrogen-limited medium. Microbial culture was incubated at 30°C under different agitation rates of 120, 180 and 250rpm for 120h. The repeated-batch culture was performed at three harvesting times of 12, 24 and 48h using four harvesting cultures of 60%, 70%, 80% and 90%. Experimental results revealed that nitrogen source (ammonium tartrate) was fully utilized by C. bainieri 2A1 within 24h in all agitation rates tested. It was also observed that a high amount of glucose in culture medium was consumed by C. bainieri 2A1 at 250rpm agitation speed during the batch fermentation. Similar results showed that the highest lipid concentration of 2.96g/L was obtained at an agitation rate of 250rpm at 120h cultivation time with the maximum lipid productivity of 7.0×10−2mg/ml/h. On the other hand, experimental results showed that the highest lipid concentration produced in the repeated-batch culture was 3.30g/L at the first cycle of 48h harvesting time using 70% harvesting volume, while 0.23g/L gamma-linolenic acid (GLA) was produced at the last cycle of 48h harvesting time using 80% harvesting volume

Transcriptomic Response Of Salmonella enterica Subspecies enterica serovar Typhi To Antibiotic Treatments During Biofilm Formation

Salmonella Typhi (S. Typhi) is a human-specific pathogen which causes typhoid fever. One major factor contributing to typhoid persistence is the existence of asymptomatic typhoid carriers. Biofilm formation in the human gallbladder is postulated to be associated with development of the carrier-state. The aim of this study was to develop an optimized assay for S. Typhi biofilm formation in vitro that mimics the environment of the gallbladder. Six key variables involved in S. Typhi biofilm formation were optimized using Response Surface Methodology (RSM), and the resulting assay formed the basis for transcriptomic investigation of biofilm production, in the presence of the antibiotics kanamycin and chloramphenicol

Repeated Batch Fermentation Biotechnology for the Biosynthesis of Lipid and Gamma-Linolenic Acid by Cunninghamella bainieri 2A1

The biosynthesis of biomedical products including lipid and gamma-linolenic acid (GLA) by Cunninghamella bainieri 2A1 was studied in repeated batch fermentation. Three key process variables, namely, glucose concentration, ammonium tartrate concentration, and harvesting time, were optimized using response surface methodology. Repeated batch fermentation was carried out by the cultivation of Cunninghamella bainieri 2A1 in nitrogen-limited medium with various nitrogen concentration (1–4 g/L) and glucose concentration (20–40 g/L) at three time intervals (12 h, 24 h, and 48 h). Experimental results showed that the highest lipid concentration of 6.2 g/L and the highest GLA concentration of 0.4 g/L were obtained in optimum conditions, where 20.2 g/L glucose, 2.12 g/L ammonium tartrate, and 48 h harvesting time were utilized. Statistical results showed that the interaction between glucose and ammonium tartrate concentration had highly significant effects on lipid and GLA biosynthesis (P<0.01). Moreover, harvesting time had a significant interaction effect with glucose and ammonium tartrate concentration on lipid production (P<0.05)

Recent Advances in Synthesis and Degradation of Lignin and Lignin Nanoparticles and Their Emerging Applications in Nanotechnology

Lignin is an important commercially produced polymeric material. It is used extensively in both industrial and agricultural activities. Recently, it has drawn much attention from the scientific community. It is abundantly present in nature and has significant application in the production of biodegradable materials. Its wide usage includes drug delivery, polymers and several forms of emerging lignin nanoparticles. The synthesis of lignin nanoparticles is carried out in a controlled manner. The traditional manufacturing techniques are costly and often toxic and hazardous to the environment. This review article highlights simple, safe, climate-friendly and ecological approaches to the synthesis of lignin nanoparticles. The changeable, complex structure and recalcitrant nature of lignin makes it challenging to degrade. Researchers have discovered a small number of microorganisms that have developed enzymatic and non-enzymatic metabolic pathways to use lignin as a carbon source. These microbes show promising potential for the biodegradation of lignin. The degradation pathways of these microbes are also described, which makes the study of biological synthesis much easier. However, surface modification of lignin nanoparticles is something that is yet to be explored. This review elucidates the recent advances in the biodegradation of lignin in the ecological system. It includes the current approaches, methods for modification, new applications and research for the synthesis of lignin and lignin nanoparticles. Additionally, the intricacy of lignin&rsquo;s structure, along with its chemical nature, is well-described. This article will help increase the understanding of the utilization of lignin as an economical and alternative-resource material. It will also aid in the minimization of solid waste arising from lignin