Statistical optimization of solid state fermentation conditions for the enhanced production of thermoactive chitinases by mesophilic soil fungi using response surface methodology and their application in the reclamation of shrimp processing by-products

Fusarium as a promising fungal genus with potential application in bioremediation for pollutants mitigation: A review

Fusarium is genetically diverse and widely distributed geographically. It is one of the genera with more endophytes (which cause no damage to the host plants). This review highlights the capability of Fusarium species to degrade environmental pollutants and describes the biodegradation pathways of some of the emerging environmental contaminants. Some Fusarium species use metabolic strategies enabling them to efficiently mineralize high concentrations of toxic environmental pollutants. These fungi can degrade hydrocarbons, pesticides, herbicides, dyes, pharmaceutical compounds, explosives, plastics, and plastic additives, among other pollutants, and possess high metal biosorption capabilities. According to data from consulted reports, Fusarium strains showed a percentage of biodegradation of a variety of contaminants ranging between 30 % and 100 % for different tested concentrations (from 1 mg to 10 g/L) in a time range between 10 h and 90 d. Enzymes such as esterase, cutinase, laccase, lignin peroxidase, manganese peroxidase, dehydrogenase, lipase, dioxygenase, and phosphoesterase were detected during the pollutant biodegradation process. Fusarium oxysporum, Fusarium solani, and Fusarium culmorum are the most studied species of this genus. Owing to their metabolic versatility, these fungal species and their enzymes represent promising tools for bioremediation applications to mitigate the adverse effects of environmental pollution.

Anti-listerial peptides from a marine Bacillus velezensis FTL7: production optimization, characterizations and molecular docking studies

Antimicrobial peptides (AMPs) with potent anti-listerial activity were characterized from a novel marine Bacillus velezensis FTL7. A Box-Behnken statistical experimental design was used to study the combined impact of culture conditions on the production of AMPs by B. velezensis FTL7. The conditions optimized by statistical experimental design were 34.5 °C incubation temperature, 23 h incubation time, and 7.6 initial pH of the medium. AMP purification was performed by ammonium sulphate fractionation and butanol extraction followed by reversed-phase C18 solid-phase extraction. Tricine-SDS-PAGE analysis revealed a peptide with a molecular mass of ~ 6.5 kDa in an active AMPs fraction, whereas the mass spectrometry (MS) analysis showed the presence of AMPs in the mass range of 1-1.6 kDa, along with a 6.5 kDa peptide. Both MS and MS/MS analysis confirmed the AMPs as lipopeptides including surfactin, fengycins and iturin A and a circular bacteriocin amylocyclicin. The minimum inhibitory concentration of these AMPs against L. monocytogenes Scott A was 2.5 µg/mL. Further, the in-silico docking studies showed that the AMPs from B. velezensis FTL7 have high binding energy and stable binding patterns towards L. monocytogenes target proteins. Thus, this new combination of AMPs can serve as an effective food bio-preservative.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-024-03944-5.

Screening of Chitinolytic Microfungi and Optimization of Parameters for Hyperproduction of Chitinase Through Solid-State Fermentation Technique

This study is intended for the production of chitinase enzyme from locally isolated fungal strains. Out of 10 isolated fungal strains from district Gujrat, Punjab, Pakistan, Aspergillus terreus SB3 (accession number ON738571) was found with maximum chitinolytic potential (80.8 U/mL/min). By applying central composite design (CCD) through response surface methodology (RSM) under solid-state fermentation (SSF), eight nutritional and physical parameters were optimized. Among these, temperature, substrate concentration, and pH were found as significant factors toward chitinase production in the first phase. Moisture and nitrogen source were found as significant factors during second phase of chitinase production. The effect of incubation period, inoculum size, and magnesium source was observed as non-significant. The chitinase activity was successfully enhanced more than 2 folds up to 198.5 U/mL/min at optimized conditions of 35 °C temperature, 4.5 pH, 20 g substrate concentration, 4-day incubation period, 55% moisture content, 4.5 mL inoculum size, 0.25 g ammonium sulfate, and 0.30 g magnesium sulfate using RSM design. It was also found that Ganoderma lucidum (bracket fungus) has more potential to be used for the production of chitinase compared to fish scales. The present study exhibited Aspergillus terreus SB3 (ON738571) as a potential indigenous strain capable for hyperproduction of chitinase through cheap fermentation technology that might be employed for the eradication of chitin-based sea waste to remove the marine pollution.

Characterization of different chitosanases of Bacillus strains and their application in chitooligosaccharides production

Chitosanases are potential candidates for chitooligosaccharides (COS) production-based industries, therefore, the discovery of chitosanases having commercial potential will remain a priority worldwide. This study aims to characterize different chitosanases of Bacillus strains for COS production. Six different indigenous Bacillus strains (B. cereus EGE-B-6.1m, B. cereus EGE-B-2.5m, B. cereus EGE-B-5.5m, B. cereus EGE-B-10.4i, B. thuringiensis EGE-B-3.5m, and B. mojavensis EGE-B-5.2i) were used to purify and characterize chitosanases. All purified chitosanases have a similar molecular weight (37 kDa) as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. However, other characteristics such as optimum temperature and pH, kinetic parameters (K_m and V_max ), temperature, and pH stabilities were dissimilar among the strains of different Bacillus species and within the same species. Furthermore, chitosanases of all strains were able to successfully hydrolyze chitosan to COS and oligomers of the degree of polymerization 2-6 were detected with chitobiose and chitotriose as major hydrolysis products. The relative yields of COS were in a range of 19%-31% and chitosanase of B. thuringiensis EGE-B-3.5m turned out to be the best enzyme in terms of its characteristics and COS production potential with maximum relative yield (31%). Results revealed that Bacillus chitosanases could be used directly for efficient bioconversion of chitosan into COS and will be valuable for large-scale production of biologically active COS.

Chitinase production by Trichoderma koningiopsis UFSMQ40 using solid state fermentation

The chitinases have extensive biotechnological potential but have been little exploited commercially due to the low number of good chitinolytic microorganisms. The purpose of this study was to identify a chitinolytic fungal and optimize its production using solid state fermentation (SSF) and agroindustry substrate, to evaluate different chitin sources for chitinase production, to evaluate different solvents for the extraction of enzymes produced during fermentation process, and to determine the nematicide effect of enzymatic extract and biological control of Meloidogyne javanica and Meloidogyne incognita nematodes. The fungus was previously isolated from bedbugs of Tibraca limbativentris Stal (Hemiptera: Pentatomidae) and selected among 51 isolated fungal as the largest producer of chitinolytic enzymes in SSF. The isolate UFSMQ40 has been identified as Trichoderma koningiopsis by the amplification of tef1 gene fragments. The greatest chitinase production (10.76 U gds^-1) occurred with wheat bran substrate at 55% moisture, 15% colloidal chitin, 100% of corn steep liquor, and two discs of inoculum at 30 °C for 72 h. Considering the enzymatic inducers, the best chitinase production by the isolated fungus was achieved using chitin in colloidal, powder, and flakes. The usage of 1:15 g/mL of sodium citrate-phosphate buffer was the best ratio for chitinase extraction of SSF. The Trichoderma koningiopsis UFSMQ40 showed high mortality of M. javanica and M. incognita when applied to treatments with enzymatic filtrated and the suspension of conidia.

The Statistical Optimisation of Recombinant β-glucosidase Production through a Two-Stage, Multi-Model, Design of Experiments Approach

β-glucosidases are a class of enzyme that are widely distributed in the living world, with examples noted in plants, fungi, animals and bacteria. They offer both hydrolysis and synthesis capacity for a wide range of biotechnological processes. However, the availability of native, or the production of recombinant β-glucosidases, is currently a bottleneck in the widespread industrial application of this enzyme. In this present work, the production of recombinant β-glucosidase from Streptomyces griseus was optimised using a Design of Experiments strategy, comprising a two-stage, multi-model design. Three screening models were comparatively employed: Fractional Factorial, Plackett-Burman and Definitive Screening Design. Four variables (temperature, incubation time, tryptone, and OD600 nm) were experimentally identified as having statistically significant effects on the production of S.griseus recombinant β-glucosidase in E. coli BL21 (DE3). The four most influential variables were subsequently used to optimise recombinant β-glucosidase production, employing Central Composite Design under Response Surface Methodology. Optimal levels were identified as: OD600 nm, 0.55; temperature, 26 °C; incubation time, 12 h; and tryptone, 15 g/L. This yielded a 2.62-fold increase in recombinant β-glucosidase production, in comparison to the pre-optimised process. Affinity chromatography resulted in homogeneous, purified β-glucosidase that was characterised in terms of pH stability, metal ion compatibility and kinetic rates for p-nitrophenyl-β-D-glucopyranoside (pNPG) and cellobiose catalysis.