Study of different media for production of penicillin G acylase from Bacillus megaterium ATCC 14945

Optimization of a medium composition for the heterologous production of Alcaligenes faecalis penicillin G acylase in Bacillus megaterium

Penicillin G acylase (PGA) is a strategic enzyme in the production processes of beta-lactam antibiotics. High demand for β-lactam semisynthetic antibiotics explain the genetic and biochemical engineering strategies devoted towards novel ways for PGA production and application. This work presents a fermentation process for the heterologous production of PGA from Alcaligenes faecalis in Bacillus megaterium with optimization. The thermal stability from A. faecalis PGA is considerably higher than other described PGA and the recombinant enzyme is secreted to the culture medium by B. megaterium, which facilitates the separation and purification steps. Media optimization using fractional factorial design experiments was used to identify factors related to PGA activity detection in supernatant and cell lysates. The optimized medium resulted in almost 6-fold increased activity in the supernatant samples when compared with the basal medium. Maximum enzyme activity in optimized medium composition achieves values between 135 and 140 IU/ml. The results suggest a promising model for recombinant production of PGA in B. megaterium with possible extracellular expression of the active enzyme.

Multipurpose efficacy of the lyophilized cell-free supernatant of Salmonella bongori isolated from the freshwater fish, Devario aequipinnatus: toxicity against microbial pathogens and mosquito vectors

Presently, the discovery of effective drugs and pesticides from eco-friendly biological sources is an important challenge in the field of life sciences. The present research was aimed for standardizing an innovative approach in the evaluation of the biological potentiality of the metabolites of fish-associated bacteria. We have identified 17 skin-associated bacteria from the freshwater fish, giant danio, Devario aquipinnatus. They were screened through biofilm forming and extracellular enzyme producing ability. The results of preliminary antibacterial evaluation of the bacterial supernatants underlined the importance of three potential strains (BH8, BH10 and BH11) for further applied research. Hence, such strains were subsequently subjected to a novel extraction procedure to overcome the difficulties found in polar solvents mixed with the supernatant. The lyophilized cell-free supernatant (LCFS) of 3 isolates were individually extracted by using methanol. During the testing of LCFS's methanolic extract (LCFS-ME) of 3 isolates, only the extract of BH11-strain exhibited potent inhibitory activity against the pathogenic bacteria and fungi. Furthermore, the larvicidal and mosquitocidal assays on the filariasis vector, Culex quinquefasciatus also showed its potent toxicity on both the adults and developmental instars of mosquito. Through molecular and phylogenetic analyses, the BH11 strain was identified as Salmonella bongori (KR350635). The present finding emphasized that the S. bongori could be an important novel source of effective antimicrobials and mosquitocidal agents.

Biotechnological advances on penicillin G acylase: pharmaceutical implications, unique expression mechanism and production strategies

In light of unrestricted use of first-generation penicillins, these antibiotics are now superseded by their semisynthetic counterparts for augmented antibiosis. Traditional penicillin chemistry involves the use of hazardous chemicals and harsh reaction conditions for the production of semisynthetic derivatives and, therefore, is being displaced by the biosynthetic platform using enzymatic transformations. Penicillin G acylase (PGA) is one of the most relevant and widely used biocatalysts for the industrial production of β-lactam semisynthetic antibiotics. Accordingly, considerable genetic and biochemical engineering strategies have been devoted towards PGA applications. This article provides a state-of-the-art review in recent biotechnological advances associated with PGA, particularly in the production technologies with an emphasis on using the Escherichia coli expression platform.

Getting the big beast to work--systems biotechnology of Bacillus megaterium for novel high-value proteins

The high industrial relevance of the soil bacterium Bacillus megaterium as host for recombinant proteins is driving systems-wide analyses of its metabolic and regulatory networks. The present review highlights novel systems biology tools available to unravel the various cellular components on the level of metabolic and regulatory networks. These provide a rational platform for systems metabolic engineering of B. megaterium. In line, a number of interesting studies have particularly focused on studying recombinant B. megaterium in its industrial bioprocess environment thus integrating systems metabolic engineering with systems biotechnology and providing the full picture toward optimal processes.

Comparing the performance of multilayer perceptrons networks and neuro-fuzzy systems for on-line inference of Bacillus megaterium cellular concentrations

Penicillin G acylase (PGA) is one of the most important enzymes for the pharmaceutical industry. Bacillus megaterium has the advantage of producing extra-cellular PGA. This work compares two neural networks (NNs) architectures for on-line inference of B. megaterium cell mass in an aerated stirred tank bioreactor, during the production of PGA. Nowadays, intelligent computing tools such as artificial NNs and fuzzy logic are commonly applied for state inference and modeling of bioreactors. Combining these two approaches in hybrid, neuro-fuzzy systems, may be advantageous. Our results indicate that a neuro-fuzzy inference system showed a better performance to infer cell concentrations, when compared to multilayer perceptrons networks.

The penicillin G acylase production byB. megaterium is amino acid consumption dependent

Aiming at to enhance the production of penicillin G acylase (PGA) by Bacillus megaterium, we have performed flasks experiments using different medium composition. Using 51 g/L of casein hydrolyzed with Alcalase and 2.7 g/L of phenylacetic acid (PhAc), the following carbon substrates were tested, individually and combined: glucose, glycerol, and lactose (present in cheese whey). Glycerol and glucose showed to be effective nutrients for the microorganism growth but delayed the PGA production. Cheese whey always increased enzyme production and cell mass. However, lactose (present in cheese whey) was not a significant carbon source for B. megaterium. PhAc, amino acids, and small peptides present in the hydrolyzed casein were the actual carbon sources for enzyme production. Replacement of hydrolyzed casein by free amino acids, 10.0 g/L, led to a significant increase in enzyme production (app. 150%), with a preferential consumption of alanine, aspartic acid, glycine, serine, arginine, threonine, lysine, and glutamic acid. A decrease of the enzyme production was observed when 20.0 g/L of amino acids were used. Using the single omission technique, it was shown that none of the 18 tested amino acids was essential for enzyme production. The use of a medium containing eight of the preferentially consumed amino acids lead to similar enzyme production level obtained when using 18 amino acids. PhAc, up to 2.7 g/L, did not inhibit enzyme production, even if added at the beginning of the cultivation.

High yield recombinant penicillin G amidase production and export into the growth medium using Bacillus megaterium

Background

During the last years B. megaterium was continuously developed as production host for the secretion of proteins into the growth medium. Here, recombinant production and export of B. megaterium ATCC14945 penicillin G amidase (PGA) which is used in the reverse synthesis of β-lactam antibiotics were systematically improved.

Results

For this purpose, the PGA leader peptide was replaced by the B. megaterium LipA counterpart. A production strain deficient in the extracellular protease NprM and in xylose utilization to prevent gene inducer deprivation was constructed and employed. A buffered mineral medium containing calcium ions and defined amino acid supplements for optimal PGA production was developed in microscale cultivations and scaled up to a 2 Liter bioreactor. Productivities of up to 40 mg PGA per L growth medium were reached.

Conclusion

The combination of genetic and medium optimization led to an overall 7-fold improvement of PGA production and export in B. megaterium. The exclusion of certain amino acids from the minimal medium led for the first time to higher volumetric PGA activities than obtained for complex medium cultivations.