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Propionic acid (PA) is an important organic compound with extensive application in different industrial sectors and is currently produced by petrochemical processes. The production of PA by large‐scale fermentation processes presents a bottleneck, particularly due to low volumetric productivity. In this context, the present work aimed to produce PA by a biochemical route from a hemicellulosic hydrolysate of sorghum bagasse using the strain Propionibacterium acidipropionici CIP 53164. Conditions were optimized to increase volumetric productivity and process efficiency. Initially, in simple batch fermentation, a final concentration of PA of 17.5 g⋅L−1 was obtained. Next, fed batch operation with free cells was adopted to minimize substrate inhibition. Although a higher concentration of PA was achieved (38.0 g⋅L−1), the response variables (YP/S = 0.409 g⋅g−1 and QP = 0.198 g⋅L−1⋅H−1) were close to those of the simple batch experiment. Finally, the fermentability of the hemicellulosic hydrolysate was investigated in a sequential batch with immobilized cells. The PA concentration achieved a maximum of 35.3 g⋅L−1 in the third cycle; moreover, the volumetric productivity was almost sixfold higher (1.17 g⋅L−1⋅H−1) in sequential batch than in simple batch fermentation. The results are highly promising, providing preliminary data for studies on scaling up the production of this organic acid. [ABSTRACT FROM AUTHOR]

Nanocellulose (NC) is a unique and promising natural material derived from native cellulose. It has attracted much attention for its versatility in construction composites, which have improved chemical and mechanical properties. This review covers the type of biomass used and NC production methods, emphasizing biotechnological routes, which promote their biological properties (biocompatibility, biodegradability and low toxicity), fundamental for medical applications. NC has many hydroxyl groups on its surface, enabling its structure to be modifiable, adaptable and viable for various fields. Furthermore, NC‐based biosensors are suitable for food quality control, monitoring environmental analytes, and particularly in health diagnostics, such as COVID19 detection. The developed analytical devices were described in a table, including information about the sensor molecule, reading system, analyte, range, detection limit, sensitivity and analytical performance. [ABSTRACT FROM AUTHOR]

Although analytical methods (often offline) are considered as references (gold standards) for monitoring industrial bioprocesses, real-time monitoring (online) is always preferable for maximizing such processes. However, many of the real-time methods that measure total cell concentration cannot distinguish living micro-organisms from the dead ones or even other materials. Moreover, some real-time methods also lead to possible wrong results when the micro-organism involved in the bioprocess exhibits significant metabolic, physiological, and kinetic changes as it grows. This study presents a real-time technique intended to monitor this class of micro-organisms and that is based on an alternative method of bioimpedance spectroscopy. The feasibility of the proposed technique was evaluated during bacterial growth experiments using the bacteria Bacillus thuringiensis var. israelensis (Bti) with initial inocula of 5%, 10%, and 15% (v/v on 220 ml). Each growth experiment was monitored every hour over 18 h by the proposed technique and by a classical offline method (McFarland method). The results of monitoring the studied bioprocess by both methods exhibited an average Pearson correlation coefficient ( r ̄ ) of above 0.9 and good agreement when the Bland–Altman method was used to compare them. [ABSTRACT FROM AUTHOR]

Enzymatic hydrolysis processes can change the physical characteristics of nanocellulose derived from Kraft pulp. Among these attributes are its crystallinity index and dimensions. In this study, we determined the optimal conditions under which nanocellulose could be produced enzymatically with the greatest increase of the crystallinity index relative to its initial state. Application of Central Composite Rotatable Design statistical analysis to the experiments was employed to direct an increase the crystallinity index in 10% at the 24‐H hydrolysis time. Upon establishment of ideal levels of starting material and enzyme, reactions were carried out at hydrolysis times of 24, 48, and 72 H under these ideal parameters. The effectiveness of deagglomeration was demonstrated by measuring the hydrodynamic diameter of the particles by dynamic light scattering. Scanning electron microscopy was performed on four samples, the original material, kraft pulp, and hydrolyzed biomaterials at 72 H in the ideal parameters. The hydrolyzed material with the best statistical data, revealing a fiber diameter of 180 nm, disclosing to be biomaterial with nanocellulose dimensions. [ABSTRACT FROM AUTHOR]

Research demonstrates AOX1 promoter efficiently produces Thermomyces lanuginosus xylanase in Pichia pstoris. Data indicate that cell density greatly influences the xylanase expression followed by methanol and yeast nitrogen base concentration.