Correction: Bodea et al. Optimization of Moist and Oven-Dried Bacterial Cellulose Production for Functional Properties. Polymers 2021, 13, 2088

The authors wish to make a change to the published paper [1]. In Table 2 and Table 3, the units of Fiber Diameter have been changed from “µm” to “nm”. Also, in the footnotes of Tables 4 and 5, the units of Fiber Diameter have been changed from “µm” to “nm”. The mistake was due to the authors’ oversight. To avoid misleading readers, we would like to update the data in the article. The authors apologize for any inconvenience this may have caused.

The manuscript will be updated, and the original will remain online on the article webpage: https://www.mdpi.com/2073-4360/13/13/2088.

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Tables

Table 2

The properties of bacterial cellulose (BC) of interest for biomedical purposes at different fermentation conditions based on a Box–Behnken design for response surface methodology (RSM).

	Independent Variables			Response—Dependent Variables												Desir
	X1Harvest(d)	X2Inoculum Volume(mL)	X3BC Type	Y1Thickness *(mm)		Y2 Half-Swelling Time(h)		Y3Drug Half-Release Time(h)		Y4Tensile Strength σ(MPa)		Y5Young’s Modulus E(MPa)		Y6Fiber Diameter(nm)
				exp	pred **	exp	pred **	exp	pred **	exp	pred **	exp	pred **	exp	pred **
1	6	1	dry	1.68 ± 0.16 bc	1.62	1.25 ± 0.5 bc	1.11	4.95 ± 0.77 de	5.63	7.61 ± 0.21 ab	7.88	128.92 ± 30.37 b	118.19	51.34 ± 6.99 a	50.18	0.40
2	18	1	dry	2.67 ± 0.67 ab	2.81	1.92 ± 0.89 ab	1.89	3.68 ± 0.32 e	5.36	10.34 ± 3.69 a	9.85	139.34 ± 22.35 b	142.08	41.40 ± 3.87 de	42.40	0.48
3	12	3	dry	2.09 ± 0.15 ab	1.93	0.99 ± 0.38 c	1.50	12.78 ± 3.45 a	10.28	10.04 ± 1.90 a	8.86	117.86 ± 28.18 b	133.85	46.00 ± 7.61 bcd	46.33	0.57
4	6	5	dry	1.34 ± 0.15 c	1.05	1.22 ± 0.6 bc	1.11	9.12 ± 1.60 b	8.88	7.08 ± 2.78 abc	7.88	143.99 ± 36.54 a	160.75	47.11 ± 8.77 abc	47.82	0.41
5	18	5	dry	2.28 ± 0.23 ab	2.23	2.12 ± 0.84 a	1.89	8.25 ± 1.61 bcd	8.61	9.22 ± 3.33 a	9.85	209.39 ± 23.85 c	184.64	45.78 ± 6.05 bcd	44.90	0.53
6	6	1	moist	1.68 ± 0.16 bc	1.62	2.47 ± 0.20 a	2.52	5.93 ± 0.58 bcde	3.81	3.02 ± 0.64 d	2.45	16.03 ± 2.97 c	13.26	49.30 ± 4.18 ab	50.54	0.29
7	18	1	moist	2.67 ± 0.67 ab	2.81	2.53 ± 0.28 a	2.54	3.77 ± 1.76 e	3.54	4.64 ± 0.32 bcd	4.42	26.38 ± 15.22 c	37.15	43.67 ± 4.19 cde	42.75	0.41
8	12	3	moist	2.09 ± 0.15 ab	1.93	2.68 ± 0.18 a	2.53	5.97 ± 2.25 bcde	8.46	2.91 ± 0.83 d	3.44	21.59 ± 11.90 c	5.60	45.49 ± 2.64 bcde	44.83	0.54
9	6	5	moist	1.34 ± 0.15 c	1.05	2.49 ± 0.38 a	2.52	5.38 ± 1.95 cde	7.06	2.61 ± 0.38 d	2.45	12.44 ± 0.73 c	9.18	45.12 ± 6.03 bcde	44.48	0.36
10	18	5	moist	2.28 ± 0.23 ab	2.23	2.47 ± 0.08 a	2.54	8.60 ± 2.81 bc	6.79	4.00 ± 0.55 cd	4.42	21.82 ± 2.47 c	33.07	40.60 ± 4.99 e	41.56	0.57
p-value ***				0.992		0.824		0.853		0.897		0.971		0.912

Where exp—experimental values; pred—values predicted by the RSM model; desir—overall desirability (0…1); *—the thickness was measured for the entire batch, before drying (n = 6); ** the predicted value resulted from the model optimizing the BC properties; *** Mann–Whitney two-tailed test (α = 0.001) of the experimental data versus the values predicted by the model optimizing the BC properties. Note: The data are presented as mean ± SD. Different letters (a–e within the same column show significant differences among the samples (Fisher (LSD), p < 0.05).

Table 3

Model parameters (coded coefficients), p values, and goodness-of-fit statistics obtained by response surface methodology (RSM) for each of the 6 response variables (Yi).

		Y1Thickness(mm)		Y2Half-Swelling Time(h)		Y3Drug Half-ReleaseTime (h)		Y4Tensile Strengthσ (MPa)		Y5Young’s Modulus E(MPa)		Y6Fiber Diameter(nm)		Desirability
		coef	p	coef	p	coef	p	coef	p	coef	p	coef	p	coef	p
intercept	b0	1.926 ***	0.000	2.013 ***	0.000	9.370 ***	0.000	6.149 ***	0.000	69.720 ***	0.000	45.580 ***	0.000	0.553 ***	0.000
linear	b1	0.591 ***	0.002	0.203 *	0.054	−0.135	0.793	0.985 **	0.012	11.940 **	0.025	−2.677 ***	0.000	0.066 ***	0.000
	b2	−0.289 ***	0.000	NA	NA	1.627 ***	0.004	NA	NA	9.620 *	0.066	−0.889 *	0.132	0.0339 ***	0.000
	b3 (dry)	NA	NA	−0.514 ***	0.000	0.911 *	0.056	2.711 ***	0.000	64.120 ***	0.000	0.747	0.156	0.0216 ***	0.000
interaction	b12	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	1.215 **	0.044	0.0166 ***	0.000
	b13	NA	NA	0.191 *	0.068	NA	NA	NA	NA	NA	NA	NA	NA	−0.017 ***	0.000
	b23	NA	NA	NA	NA	NA	NA	NA	NA	11.660 **	0.028	0.924 *	0.118	−0.0219 ***	0.000
square	b11	NA	NA	NA	NA	−3.16 *	0.010	NA	NA	NA	NA	NA	NA	NA	NA
	b22	NA	NA	NA	NA	NA	NA	NA	NA	17.600 *	0.129	NA	NA	−0.123 ***	0.000
	b33	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA
R2		0.70	-	0.61	-	0.47	-	0.73	-	0.90	-	0.59	-	0.995	-
Lack-of-fit		-	0.954	-	0.638	-	0.455	-	0.886	-	0.440	-	0.590	-	-
The model		-	0.000	-	0.000	-	0.003	-	0.000	-	0.000	-	0.000	-	0.000

Note: The explanatory variables were coef—coded coefficients, X₁: harvest (d), X₂: inoculum volume (mL), X₃: membrane type. A stepwise selection of terms was used with α ≤ 0.15 for a hierarchical model; NA—not applicable, the parameter was removed from the model. * significant at p < 0.15, ** significant at p < 0.05, *** significant at p < 0.01.

Reference

1. Bodea, I.M.; Beteg, F.I.; Pop, C.R.; David, A.P.; Dudescu, M.C.; Vilău, C.; Stănilă, A.; Rotar, A.M.; Cătunescu, G.M. Optimization of Moist and Oven-Dried Bacterial Cellulose Production for Functional Properties. Polymers; 2021; 13, 2088. [DOI: https://dx.doi.org/10.3390/polym13132088] [PubMed: https://www.ncbi.nlm.nih.gov/pubmed/34202870]