**4. Lipase**

Lipases (EC 3.1.1.x) are enzymes degrading lipids. In literature, most of the studied and reported lipases are triacylglycerol lipases (EC 3.1.1.3), while additionally there are carboxylesterase (EC 3.1.1.1) which hydrolyze carboxylic ester bonds, arylesterase (EC 3.1.1.2) also acting on carboxylic esters but more specifically on phenolic esters, phospholipase A2 (EC 3.1.1.4) again hydrolyzing carboxylic esters specifically on phosphatidylcholine. It should be noted that distinguishing each of these enzymes is rather challenging as they have similar activities.

The producing organisms span the fungi and bacteria, in particular *B. subtilis* [44], *E. coli* [45] for EC 3.1.1.1 (carboxyl esterase), *Gluconobacter oxydans* [46] and *Lactobacillus casei* [47] for EC 3.1.1.2 (arylesterases) and *Acinetobacter calcoaceticus, B. subtilis, Chromobacterium viscosum, Micrococcus freudenreichii, Lactobacillus delbruckii, P. aeruginosa* and *Streptococcus lactis* [48] for EC 3.1.1.3 (triacylglycerol lipase)

are reported to be inhibitors. Interestingly, sodium dodecylsulfate (SDS), urea and 2-mercaptoethanol are reported to be both activating [21, 22] and inhibiting [17, 18] compounds. The production of enzymes is typically performed in submerged fermentation, less often via solid state fermentation, typically under mesophilic conditions, moderate pH and temperature (30–50°C, mostly in 37°C; pH range of 3–9, mostly at 7) in chemically defined

source), lactose, maltose glucose or starch as C-source, using chiefly *Bacillus* species [23–27]. Additionally, agro-wastes are also used as substrates and inducers as coconut oil cake, wheat/ rice bran, spent brewing grain, cassava bagasse, jackfruit or tamarind seed powder, palm

Phosphatases belong to the enzyme group responsible in the hydrolysis of ester-phosphate bonds which releases phosphates. These are sub-classified as phosphomonoesterases (EC 3.1.3.x), phosphodiesterases (EC 3.1.4.x), enzymes that hydrolyze phosphorus-containing anhydrides (EC 3.6.1.x), P-N bonds (EC 3.9.1.x) and various groups that act on this bonds. From an application point of view, these are grouped as alkaline, acid phosphatases and inorganic diphosphatases. The microbial producers of these enzymes are numerous, including *B. subtilis* [28], *Escherichia coli* [29] and *Pseudomonas aeruginosa* [30] for alkaline phosphatase; *Acidithiobacillus thiooxidans* [31], *E. coli* [32] and *Lactobacillus curvatus* [33] for acid phosphatase and *Geobacillus stearothermophilus*

[34], *Rhodobacter capsulatus, Rhodopseudomonas palustris* [35] for Inorganic diphosphatase.

is also a range for the molecular weight, from 32.5 [42] to 128 [43] kDa.

, MnCl2

The large portfolio of phosphatases works in a broad range of pH and temperature. For the pH, the phosphatases are reported to work optimally between 2.5 [36] and 12.5 [37]. As for the temperature, active ranges are reported to be between 5 [38] and 95°C [39], while optimally, the enzyme works between 20 and 70°C [40, 41]. With different pockets or binding sites, there

Several agents are reported to inhibit the phosphatases. These are ascorbate, dithiothreitol,

Lipases (EC 3.1.1.x) are enzymes degrading lipids. In literature, most of the studied and reported lipases are triacylglycerol lipases (EC 3.1.1.3), while additionally there are carboxylesterase (EC 3.1.1.1) which hydrolyze carboxylic ester bonds, arylesterase (EC 3.1.1.2) also acting on carboxylic esters but more specifically on phenolic esters, phospholipase A2 (EC 3.1.1.4) again hydrolyzing carboxylic esters specifically on phosphatidylcholine. It should be noted that distinguishing each of these enzymes is rather challenging as they have similar activities.

[32], 1,10-phenanthroline, EDTA [33] have been found to stimulate enzyme activity.

, sodium lauryl sulfate, tartrate [31], 2-mercaptoethanol, BaCl2

[33]. In contrast, some organic acids, for example, citrate, pyruvate, succinate

, p-chloromercuribenzoate (PCMB), PMSF, tripolyphos-

, CaCl2 ,

as K-source) or complex media (yeast extract as N and K

((NH<sup>4</sup> ) 2

**3. Phosphatase**

228 Enzyme Inhibitors and Activators

NaF, molybdate, NaBH<sup>4</sup>

phate and ZnCl2

**4. Lipase**

hexametaphosphate, HgCl2

HPO4 as N-source, KH2

PO<sup>4</sup>

kernel, olive oil or mustard oil cake and rice husk [27].

Bacterial lipases has a pH working range between 4 [49] and 12 [50], while optimum pH is reported to vary between 6 [51] and 11 [52]. As for the temperature, there is a large range between 0 [53] and 100°C [54], while the optimum temperature for enzyme activity vary between 10 [55] and 90°C [50]. A span of molecular weights is reported for this enzyme (bacterial variants) from 11 [56] to 840 [57] kDa.

Metals ions such as Cu2+, Fe2+, Fe3+, Hg2+, Zn2+, Ag+ , Co2+, Ni2+, Na+ and ascorbic acid are reported to have inhibitory effect on the carboxylesterase activity [58, 59] as well as sodium dodecylsulfate (SDS), diisopropylfluorophosphate, eserine, sodium fluoride [60] and phenylmethylsulfonyl fluoride (PMSF) [61]. Organic solvents such as acetone, EDTA, ethanol, isopropanol, PMSF and SDS [49] are reported to inhibit triacylglycerol lipases [62, 63]. Under lab conditions, Triton X-100, Tween-20, Tween-40, Tween-80 [64], 1,4-dioxane, acetone, dimethyl sulfoxide, ethanol and tetrahydrofuran [65] are reported activators to carboxyl esterases. Interestingly, acetone, Brij 52, cholic acid, deoxycholic acid, isopropanol, Dimethyl sulfoxide (DMSO), lithocholic acid, rhamnolipid and sodium deoxycholate are also reported as activators for triacylglycerol lipases [66].


For production of enzyme, apart from the above-listed organisms, see **Table 1**.

\* Besides olive oil, coconut oil, castor oil, groundnut oil, mustard oil, sunflower oil, Tween 20, Tween 80, cottonseed oil and soybean oil is studied as a carbon source. Beside peptone and yeast extract, gelatin and urea is also studied as organic nitrogen sources. Besides ammonium sulphate, ammonium nitrate, potassium nitrate and L-asparagine are also studied as inorganic nitrogen sources.

**Table 1.** Lipase production studies and the reported conditions.
