Statistical optimization of cultural variables for enzymatic degradation of aflatoxin B1 by Panus neostrigosus

The aim of this study is to determine the best aflatoxin B₁ degradation conditions which was optimized using a combination of the Plackett-Burman and Box-Behnken methods with Panus neostrigosus culture filtrate. Panus neostrigosus was grown in a modified Kirk Broth medium to determine optimal degradation conditions. As a result, aflatoxin B₁ was degraded under varying culture conditions. The Plackett-Burman method was designed after sixteen different experiments with fifteen variables. The three most effective variables (Sucrose, yeast extract, wheat bran) were chosen for the Box-Behnken methodology. The aflatoxin B₁ degradation rate was 49% in just 1 h exposure to culture filtrate which was obtained under optimal growth conditions; (g-ml/L) sucrose 10, yeast extract 3, wheat bran 3, soytone 5, KH₂PO₄ 2, MgSO₄.7H₂O 0.5, CaCl₂.H₂O 0.1, ammonium tartrate 2, trace element solution 10; 28 °C of incubation temperature, medium pH 5, 7.5% inoculum rate, 125 rpm of agitation speed, and a twelve-day incubation period. The SDS-PAGE studies show that the enzyme responsible for AFB₁ degradation has 38 kDa molecular weight and has no laccase or MnP activity. To the best of our knowledge, this is the first report for AFB₁ degradation by Panus neostrigosus.

Statistical optimization of lovastatin production by Omphalotus olearius (DC.) singer in submerged fermentation

In this study, culture conditions were optimized to improve lovastatin production by Omphalotus olearius, isolate OBCC 2002, using statistical experimental designs. The Plackett-Burman design was used to select important variables affecting lovastatin production. Accordingly, glucose, peptone, and agitation speed were determined as the variables that have influence on lovastatin production. In a further experiment, these variables were optimized with a Box-Behnken design and applied in a submerged process; this resulted in 12.51 mg/L lovastatin production on a medium containing glucose (10 g/L), peptone (5 g/L), thiamine (1 mg/L), and NaCl (0.4 g/L) under static conditions. This level of lovastatin production is eight times higher than that produced under unoptimized media and growth conditions by Omphalotus olearius. To the best of our knowledge, this is the first attempt to optimize submerged fermentation process for lovastatin production by Omphalotus olearius.

Flask and reactor scale production of plant growth regulators by Inonotus hispidus: optimization, immobilization and kinetic parameters

The aims of the presented study are to compare submerged, static, and solid-state fermentation in the production of gibberellic acid (GA3), indole acetic acid (IAA), and abscisic acid (ABA) by Inonotus hispidus, to optimize with a statistical approach, and to determine the kinetic parameters under flask and reactor conditions. The maximum concentrations of GA3, (2478.85 ± 68.53 mg/L), ABA, (273.26 ± 6.17 mg/L) and IAA (30.67 ± 0.19 mg/L) were obtained in submerged conditions. After optimization, these values reached 2998.85 ± 28.85, 339.47 ± 5.50, and 34.56 ± 0.25 mg/L, respectively. Immobilization of fungal cells on synthetic fiber, polyurethane foam, and alginate beads resulted in an increase in plant growth regulators (PGR) production by 5.53%- 5.79% under optimized conditions. At the reactor scale, a significant increase was observed for GA3 concentration, 5441.54 mg/L, which was 2.14 and 1.45 times higher than non-optimized and optimized conditions in the flask scale, respectively. The maximum values for ABA and IAA were 390.39 and 44.79 mg/L, respectively. Although the specific growth rate (µ) decreases relatively from non-optimized flask conditions to optimized reactor conditions, it was observed that the PGR amounts produced per liter medium (rp) and per gram biomass (Qp) increased significantly. This is the first report on the synthesis of PGR by Inonotus hispidus which could be crucial for sustainable agriculture.

Optimization and reactor-scale production of plant growth regulators by Pleurotus eryngii

The aims of the this study are to select the best cultivation type for plant growth regulator (PGR) production, to optimize PGR production with statistical experimental design, and to calculate bioprocess parameters and yield factors during PGR production by P. eryngii in flask and reactor scales. Submerged fermentation was the best cultivation type with 4438.67 ± 37.14, 436.95 ± 27.31, and 54.32 ± 3.21 mg/L of GA3, ABA, and IAA production values, respectively. The Plackett-Burman and Box-Behnken designs were used to determine effective culture parameters and interactive effects of the selected culture parameters on PGR production by Pleurotus eryngii under submerged fermentation. The statistical model is valid for predicting PGR production by P. eryngii. After these studies, maximum PGR production (7926.17 ± 334.09, 634.92 ± 12.15, and 55.41 ± 4.38 mg/L for GA3, ABA, and IAA, respectively) was reached on the 18th day of fermentation under optimized conditions. The optimum formula was 50 g/L fructose, 3 g/L NaNO3, and 1.5 g/L KH2PO4, 1 mg/L thiamine, incubation temperature 25 °C, initial medium pH 7.0, and an agitation speed of 150 rpm. The kinetics of PGR production was investigated in batch cultivation under 3-L stirred tank reactor conditions. Concentrations of GA3, ABA, and IAA of 10,545.00 ± 527.25, 872.32 ± 21.81, and 60.48 ± 3.48 mg/L were obtained at the reactor scale which were 4.1, 3.4, and 2.3 times higher than the initial screening values. The specific growth rate (µ), the volumetric (rp) and specific (Qp) PGR production rates, 486.11 mg/L/day and 107.43 mg/g biomass/day for GA3, confirmed the successful transfer of optimized conditions to the reactor scale. In the presented study, PGR production of P. eryngii is reported for the first time.

Ochratoxin A biodegradation by Agaricus campestris and statistical optimization of cultural variables

The goal of this study is to identify the optimum conditions for ochratoxin A (OTA) biodegradation by the supernatant of Agaricus campestris strain. The Plackett-Burman and Box-Behnken methods were used to determine optimum OTA degradation conditions of Agaricus campestris under various incubation conditions. The Plackett-Burman method was planned through 16 varied experiments with 15 variants. The three most potent variants, sucrose, yeast extract and wheat bran, were selected using the Box-Behnken methodology. Ochratoxin A biodegradation ratio of 46.67% has been specified in only 1 h under ideal growing conditions. This is the first report on the optimization of OTA biodegradation by Agaricus campestris. When compared to previously published articles, it can be asserted that Agaricus campestris has promise based on its OTA biodegradation ratio in only 1 h of reaction time.